FFmpeg: libavformat/wtvdec.c Source File

00001 /*
00002  * Windows Television (WTV) demuxer
00003  * Copyright (c) 2010-2011 Peter Ross <pross@xvid.org>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00028 #include "libavutil/channel_layout.h"
00029 #include "libavutil/intreadwrite.h"
00030 #include "libavutil/intfloat.h"
00031 #include "avformat.h"
00032 #include "internal.h"
00033 #include "wtv.h"
00034 #include "mpegts.h"
00035 
00036 /* Macros for formating GUIDs */
00037 #define PRI_PRETTY_GUID \
00038     "%08x-%04x-%04x-%02x%02x%02x%02x%02x%02x%02x%02x"
00039 #define ARG_PRETTY_GUID(g) \
00040     AV_RL32(g),AV_RL16(g+4),AV_RL16(g+6),g[8],g[9],g[10],g[11],g[12],g[13],g[14],g[15]
00041 #define LEN_PRETTY_GUID 34
00042 
00043 /*
00044  *
00045  * File system routines
00046  *
00047  */
00048 
00049 typedef struct {
00050     AVIOContext *pb_filesystem;  
00052     int sector_bits;     
00053     uint32_t *sectors;   
00054     int nb_sectors;      
00056     int error;
00057     int64_t position;
00058     int64_t length;
00059 } WtvFile;
00060 
00064 static int wtvfile_read_packet(void *opaque, uint8_t *buf, int buf_size)
00065 {
00066     WtvFile *wf = opaque;
00067     AVIOContext *pb = wf->pb_filesystem;
00068     int nread = 0;
00069 
00070     if (wf->error || pb->error)
00071         return -1;
00072     if (wf->position >= wf->length || url_feof(pb))
00073         return 0;
00074 
00075     buf_size = FFMIN(buf_size, wf->length - wf->position);
00076     while(nread < buf_size) {
00077         int n;
00078         int remaining_in_sector = (1 << wf->sector_bits) - (wf->position & ((1 << wf->sector_bits) - 1));
00079         int read_request        = FFMIN(buf_size - nread, remaining_in_sector);
00080 
00081         n = avio_read(pb, buf, read_request);
00082         if (n <= 0)
00083             break;
00084         nread += n;
00085         buf += n;
00086         wf->position += n;
00087         if (n == remaining_in_sector) {
00088             int i = wf->position >> wf->sector_bits;
00089             if (i >= wf->nb_sectors ||
00090                 (wf->sectors[i] != wf->sectors[i - 1] + (1 << (wf->sector_bits - WTV_SECTOR_BITS)) &&
00091                 avio_seek(pb, (int64_t)wf->sectors[i] << WTV_SECTOR_BITS, SEEK_SET) < 0)) {
00092                 wf->error = 1;
00093                 break;
00094             }
00095         }
00096     }
00097     return nread;
00098 }
00099 
00103 static int64_t wtvfile_seek(void *opaque, int64_t offset, int whence)
00104 {
00105     WtvFile *wf = opaque;
00106     AVIOContext *pb = wf->pb_filesystem;
00107 
00108     if (whence == AVSEEK_SIZE)
00109         return wf->length;
00110     else if (whence == SEEK_CUR)
00111         offset = wf->position + offset;
00112     else if (whence == SEEK_END)
00113         offset = wf->length;
00114 
00115     wf->error = offset < 0 || offset >= wf->length ||
00116                 avio_seek(pb, ((int64_t)wf->sectors[offset >> wf->sector_bits] << WTV_SECTOR_BITS)
00117                               + (offset & ((1 << wf->sector_bits) - 1)), SEEK_SET) < 0;
00118     wf->position = offset;
00119     return offset;
00120 }
00121 
00129 static int read_ints(AVIOContext *pb, uint32_t *data, int count)
00130 {
00131     int i, total = 0;
00132     for (i = 0; i < count; i++) {
00133         if ((data[total] = avio_rl32(pb)))
00134            total++;
00135     }
00136     return total;
00137 }
00138 
00146 static AVIOContext * wtvfile_open_sector(int first_sector, uint64_t length, int depth, AVFormatContext *s)
00147 {
00148     AVIOContext *pb;
00149     WtvFile *wf;
00150     uint8_t *buffer;
00151 
00152     if (avio_seek(s->pb, first_sector << WTV_SECTOR_BITS, SEEK_SET) < 0)
00153         return NULL;
00154 
00155     wf = av_mallocz(sizeof(WtvFile));
00156     if (!wf)
00157         return NULL;
00158 
00159     if (depth == 0) {
00160         wf->sectors = av_malloc(sizeof(uint32_t));
00161         if (!wf->sectors) {
00162             av_free(wf);
00163             return NULL;
00164         }
00165         wf->sectors[0]  = first_sector;
00166         wf->nb_sectors  = 1;
00167     } else if (depth == 1) {
00168         wf->sectors = av_malloc(WTV_SECTOR_SIZE);
00169         if (!wf->sectors) {
00170             av_free(wf);
00171             return NULL;
00172         }
00173         wf->nb_sectors  = read_ints(s->pb, wf->sectors, WTV_SECTOR_SIZE / 4);
00174     } else if (depth == 2) {
00175         uint32_t sectors1[WTV_SECTOR_SIZE / 4];
00176         int nb_sectors1 = read_ints(s->pb, sectors1, WTV_SECTOR_SIZE / 4);
00177         int i;
00178 
00179         wf->sectors = av_malloc(nb_sectors1 << WTV_SECTOR_BITS);
00180         if (!wf->sectors) {
00181             av_free(wf);
00182             return NULL;
00183         }
00184         wf->nb_sectors = 0;
00185         for (i = 0; i < nb_sectors1; i++) {
00186             if (avio_seek(s->pb, (int64_t)sectors1[i] << WTV_SECTOR_BITS, SEEK_SET) < 0)
00187                 break;
00188             wf->nb_sectors += read_ints(s->pb, wf->sectors + i * WTV_SECTOR_SIZE / 4, WTV_SECTOR_SIZE / 4);
00189         }
00190     } else {
00191         av_log(s, AV_LOG_ERROR, "unsupported file allocation table depth (0x%x)\n", depth);
00192         av_free(wf);
00193         return NULL;
00194     }
00195     wf->sector_bits = length & (1ULL<<63) ? WTV_SECTOR_BITS : WTV_BIGSECTOR_BITS;
00196 
00197     if (!wf->nb_sectors) {
00198         av_free(wf->sectors);
00199         av_free(wf);
00200         return NULL;
00201     }
00202 
00203     /* check length */
00204     length &= 0xFFFFFFFFFFFF;
00205     if (length > ((int64_t)wf->nb_sectors << wf->sector_bits)) {
00206         av_log(s, AV_LOG_WARNING, "reported file length (0x%"PRIx64") exceeds number of available sectors (0x%"PRIx64")\n", length, (int64_t)wf->nb_sectors << wf->sector_bits);
00207         length = (int64_t)wf->nb_sectors <<  wf->sector_bits;
00208     }
00209     wf->length = length;
00210 
00211     /* seek to initial sector */
00212     wf->position = 0;
00213     if (avio_seek(s->pb, (int64_t)wf->sectors[0] << WTV_SECTOR_BITS, SEEK_SET) < 0) {
00214         av_free(wf->sectors);
00215         av_free(wf);
00216         return NULL;
00217     }
00218 
00219     wf->pb_filesystem = s->pb;
00220     buffer = av_malloc(1 << wf->sector_bits);
00221     if (!buffer) {
00222         av_free(wf->sectors);
00223         av_free(wf);
00224         return NULL;
00225     }
00226 
00227     pb = avio_alloc_context(buffer, 1 << wf->sector_bits, 0, wf,
00228                            wtvfile_read_packet, NULL, wtvfile_seek);
00229     if (!pb) {
00230         av_free(buffer);
00231         av_free(wf->sectors);
00232         av_free(wf);
00233     }
00234     return pb;
00235 }
00236 
00245 static AVIOContext * wtvfile_open2(AVFormatContext *s, const uint8_t *buf, int buf_size, const uint8_t *filename, int filename_size)
00246 {
00247     const uint8_t *buf_end = buf + buf_size;
00248 
00249     while(buf + 48 <= buf_end) {
00250         int dir_length, name_size, first_sector, depth;
00251         uint64_t file_length;
00252         const uint8_t *name;
00253         if (ff_guidcmp(buf, ff_dir_entry_guid)) {
00254             av_log(s, AV_LOG_ERROR, "unknown guid "FF_PRI_GUID", expected dir_entry_guid; "
00255                    "remaining directory entries ignored\n", FF_ARG_GUID(buf));
00256             break;
00257         }
00258         dir_length  = AV_RL16(buf + 16);
00259         file_length = AV_RL64(buf + 24);
00260         name_size   = 2 * AV_RL32(buf + 32);
00261         if (buf + 48 + (int64_t)name_size > buf_end || name_size<0) {
00262             av_log(s, AV_LOG_ERROR, "filename exceeds buffer size; remaining directory entries ignored\n");
00263             break;
00264         }
00265         first_sector = AV_RL32(buf + 40 + name_size);
00266         depth        = AV_RL32(buf + 44 + name_size);
00267 
00268         /* compare file name; test optional null terminator */
00269         name = buf + 40;
00270         if (name_size >= filename_size &&
00271             !memcmp(name, filename, filename_size) &&
00272             (name_size < filename_size + 2 || !AV_RN16(name + filename_size)))
00273             return wtvfile_open_sector(first_sector, file_length, depth, s);
00274 
00275         buf += dir_length;
00276     }
00277     return 0;
00278 }
00279 
00280 #define wtvfile_open(s, buf, buf_size, filename) \
00281     wtvfile_open2(s, buf, buf_size, filename, sizeof(filename))
00282 
00286 static void wtvfile_close(AVIOContext *pb)
00287 {
00288     WtvFile *wf = pb->opaque;
00289     av_free(wf->sectors);
00290     av_freep(&pb->opaque);
00291     av_freep(&pb->buffer);
00292     av_free(pb);
00293 }
00294 
00295 /*
00296  *
00297  * Main demuxer
00298  *
00299  */
00300 
00301 typedef struct {
00302     int seen_data;
00303 } WtvStream;
00304 
00305 typedef struct {
00306     AVIOContext *pb;       
00307     int64_t epoch;
00308     int64_t pts;             
00309     int64_t last_valid_pts;  
00311     /* maintain private seek index, as the AVIndexEntry->pos is relative to the
00312        start of the 'timeline' file, not the file system (AVFormatContext->pb) */
00313     AVIndexEntry *index_entries;
00314     int nb_index_entries;
00315     unsigned int index_entries_allocated_size;
00316 } WtvContext;
00317 
00318 /* WTV GUIDs */
00319 static const ff_asf_guid EVENTID_SubtitleSpanningEvent =
00320     {0x48,0xC0,0xCE,0x5D,0xB9,0xD0,0x63,0x41,0x87,0x2C,0x4F,0x32,0x22,0x3B,0xE8,0x8A};
00321 static const ff_asf_guid EVENTID_LanguageSpanningEvent =
00322     {0x6D,0x66,0x92,0xE2,0x02,0x9C,0x8D,0x44,0xAA,0x8D,0x78,0x1A,0x93,0xFD,0xC3,0x95};
00323 static const ff_asf_guid EVENTID_AudioDescriptorSpanningEvent =
00324     {0x1C,0xD4,0x7B,0x10,0xDA,0xA6,0x91,0x46,0x83,0x69,0x11,0xB2,0xCD,0xAA,0x28,0x8E};
00325 static const ff_asf_guid EVENTID_CtxADescriptorSpanningEvent =
00326     {0xE6,0xA2,0xB4,0x3A,0x47,0x42,0x34,0x4B,0x89,0x6C,0x30,0xAF,0xA5,0xD2,0x1C,0x24};
00327 static const ff_asf_guid EVENTID_CSDescriptorSpanningEvent =
00328     {0xD9,0x79,0xE7,0xEf,0xF0,0x97,0x86,0x47,0x80,0x0D,0x95,0xCF,0x50,0x5D,0xDC,0x66};
00329 static const ff_asf_guid EVENTID_DVBScramblingControlSpanningEvent =
00330     {0xC4,0xE1,0xD4,0x4B,0xA1,0x90,0x09,0x41,0x82,0x36,0x27,0xF0,0x0E,0x7D,0xCC,0x5B};
00331 static const ff_asf_guid EVENTID_StreamIDSpanningEvent =
00332     {0x68,0xAB,0xF1,0xCA,0x53,0xE1,0x41,0x4D,0xA6,0xB3,0xA7,0xC9,0x98,0xDB,0x75,0xEE};
00333 static const ff_asf_guid EVENTID_TeletextSpanningEvent =
00334     {0x50,0xD9,0x99,0x95,0x33,0x5F,0x17,0x46,0xAF,0x7C,0x1E,0x54,0xB5,0x10,0xDA,0xA3};
00335 static const ff_asf_guid EVENTID_AudioTypeSpanningEvent =
00336     {0xBE,0xBF,0x1C,0x50,0x49,0xB8,0xCE,0x42,0x9B,0xE9,0x3D,0xB8,0x69,0xFB,0x82,0xB3};
00337 
00338 /* Windows media GUIDs */
00339 
00340 /* Media types */
00341 static const ff_asf_guid mediasubtype_mpeg1payload =
00342     {0x81,0xEB,0x36,0xE4,0x4F,0x52,0xCE,0x11,0x9F,0x53,0x00,0x20,0xAF,0x0B,0xA7,0x70};
00343 static const ff_asf_guid mediatype_mpeg2_sections =
00344     {0x6C,0x17,0x5F,0x45,0x06,0x4B,0xCE,0x47,0x9A,0xEF,0x8C,0xAE,0xF7,0x3D,0xF7,0xB5};
00345 static const ff_asf_guid mediatype_mpeg2_pes =
00346     {0x20,0x80,0x6D,0xE0,0x46,0xDB,0xCF,0x11,0xB4,0xD1,0x00,0x80,0x5F,0x6C,0xBB,0xEA};
00347 static const ff_asf_guid mediatype_mstvcaption =
00348     {0x89,0x8A,0x8B,0xB8,0x49,0xB0,0x80,0x4C,0xAD,0xCF,0x58,0x98,0x98,0x5E,0x22,0xC1};
00349 
00350 /* Media subtypes */
00351 static const ff_asf_guid mediasubtype_dvb_subtitle =
00352     {0xC3,0xCB,0xFF,0x34,0xB3,0xD5,0x71,0x41,0x90,0x02,0xD4,0xC6,0x03,0x01,0x69,0x7F};
00353 static const ff_asf_guid mediasubtype_teletext =
00354     {0xE3,0x76,0x2A,0xF7,0x0A,0xEB,0xD0,0x11,0xAC,0xE4,0x00,0x00,0xC0,0xCC,0x16,0xBA};
00355 static const ff_asf_guid mediasubtype_dtvccdata =
00356     {0xAA,0xDD,0x2A,0xF5,0xF0,0x36,0xF5,0x43,0x95,0xEA,0x6D,0x86,0x64,0x84,0x26,0x2A};
00357 static const ff_asf_guid mediasubtype_mpeg2_sections =
00358     {0x79,0x85,0x9F,0x4A,0xF8,0x6B,0x92,0x43,0x8A,0x6D,0xD2,0xDD,0x09,0xFA,0x78,0x61};
00359 
00360 /* Formats */
00361 static const ff_asf_guid format_videoinfo2 =
00362     {0xA0,0x76,0x2A,0xF7,0x0A,0xEB,0xD0,0x11,0xAC,0xE4,0x00,0x00,0xC0,0xCC,0x16,0xBA};
00363 
00364 static int read_probe(AVProbeData *p)
00365 {
00366     return ff_guidcmp(p->buf, ff_wtv_guid) ? 0 : AVPROBE_SCORE_MAX;
00367 }
00368 
00373 static int filetime_to_iso8601(char *buf, int buf_size, int64_t value)
00374 {
00375     time_t t = (value / 10000000LL) - 11644473600LL;
00376     struct tm *tm = gmtime(&t);
00377     if (!tm)
00378         return -1;
00379     strftime(buf, buf_size, "%Y-%m-%d %H:%M:%S", gmtime(&t));
00380     return 0;
00381 }
00382 
00387 static int crazytime_to_iso8601(char *buf, int buf_size, int64_t value)
00388 {
00389     time_t t = (value / 10000000LL) - 719162LL*86400LL;
00390     struct tm *tm = gmtime(&t);
00391     if (!tm)
00392         return -1;
00393     strftime(buf, buf_size, "%Y-%m-%d %H:%M:%S", gmtime(&t));
00394     return 0;
00395 }
00396 
00401 static int oledate_to_iso8601(char *buf, int buf_size, int64_t value)
00402 {
00403     time_t t = (av_int2double(value) - 25569.0) * 86400;
00404     struct tm *result= gmtime(&t);
00405     if (!result)
00406         return -1;
00407     strftime(buf, buf_size, "%Y-%m-%d %H:%M:%S", result);
00408     return 0;
00409 }
00410 
00411 static void get_attachment(AVFormatContext *s, AVIOContext *pb, int length)
00412 {
00413     char mime[1024];
00414     char description[1024];
00415     unsigned int filesize;
00416     AVStream *st;
00417     int64_t pos = avio_tell(pb);
00418 
00419     avio_get_str16le(pb, INT_MAX, mime, sizeof(mime));
00420     if (strcmp(mime, "image/jpeg"))
00421         goto done;
00422 
00423     avio_r8(pb);
00424     avio_get_str16le(pb, INT_MAX, description, sizeof(description));
00425     filesize = avio_rl32(pb);
00426     if (!filesize)
00427         goto done;
00428 
00429     st = avformat_new_stream(s, NULL);
00430     if (!st)
00431         goto done;
00432     av_dict_set(&st->metadata, "title", description, 0);
00433     st->codec->codec_id   = AV_CODEC_ID_MJPEG;
00434     st->codec->codec_type = AVMEDIA_TYPE_ATTACHMENT;
00435     st->codec->extradata  = av_mallocz(filesize);
00436     if (!st->codec->extradata)
00437         goto done;
00438     st->codec->extradata_size = filesize;
00439     avio_read(pb, st->codec->extradata, filesize);
00440 done:
00441     avio_seek(pb, pos + length, SEEK_SET);
00442 }
00443 
00444 static void get_tag(AVFormatContext *s, AVIOContext *pb, const char *key, int type, int length)
00445 {
00446     int buf_size = FFMAX(2*length, LEN_PRETTY_GUID) + 1;
00447     char *buf = av_malloc(buf_size);
00448     if (!buf)
00449         return;
00450 
00451     if (type == 0 && length == 4) {
00452         snprintf(buf, buf_size, "%"PRIi32, avio_rl32(pb));
00453     } else if (type == 1) {
00454         avio_get_str16le(pb, length, buf, buf_size);
00455         if (!strlen(buf)) {
00456            av_free(buf);
00457            return;
00458         }
00459     } else if (type == 3 && length == 4) {
00460         strcpy(buf, avio_rl32(pb) ? "true" : "false");
00461     } else if (type == 4 && length == 8) {
00462         int64_t num = avio_rl64(pb);
00463         if (!strcmp(key, "WM/EncodingTime") ||
00464             !strcmp(key, "WM/MediaOriginalBroadcastDateTime")) {
00465             if (filetime_to_iso8601(buf, buf_size, num) < 0) {
00466                 av_free(buf);
00467                 return;
00468             }
00469         } else if (!strcmp(key, "WM/WMRVEncodeTime") ||
00470                    !strcmp(key, "WM/WMRVEndTime")) {
00471             if (crazytime_to_iso8601(buf, buf_size, num) < 0) {
00472                 av_free(buf);
00473                 return;
00474             }
00475         } else if (!strcmp(key, "WM/WMRVExpirationDate")) {
00476             if (oledate_to_iso8601(buf, buf_size, num) < 0 ) {
00477                 av_free(buf);
00478                 return;
00479             }
00480         } else if (!strcmp(key, "WM/WMRVBitrate"))
00481             snprintf(buf, buf_size, "%f", av_int2double(num));
00482         else
00483             snprintf(buf, buf_size, "%"PRIi64, num);
00484     } else if (type == 5 && length == 2) {
00485         snprintf(buf, buf_size, "%"PRIi16, avio_rl16(pb));
00486     } else if (type == 6 && length == 16) {
00487         ff_asf_guid guid;
00488         avio_read(pb, guid, 16);
00489         snprintf(buf, buf_size, PRI_PRETTY_GUID, ARG_PRETTY_GUID(guid));
00490     } else if (type == 2 && !strcmp(key, "WM/Picture")) {
00491         get_attachment(s, pb, length);
00492         av_freep(&buf);
00493         return;
00494     } else {
00495         av_freep(&buf);
00496         av_log(s, AV_LOG_WARNING, "unsupported metadata entry; key:%s, type:%d, length:0x%x\n", key, type, length);
00497         avio_skip(pb, length);
00498         return;
00499     }
00500 
00501     av_dict_set(&s->metadata, key, buf, 0);
00502     av_freep(&buf);
00503 }
00504 
00508 static void parse_legacy_attrib(AVFormatContext *s, AVIOContext *pb)
00509 {
00510     ff_asf_guid guid;
00511     int length, type;
00512     while(!url_feof(pb)) {
00513         char key[1024];
00514         ff_get_guid(pb, &guid);
00515         type   = avio_rl32(pb);
00516         length = avio_rl32(pb);
00517         if (!length)
00518             break;
00519         if (ff_guidcmp(&guid, ff_metadata_guid)) {
00520             av_log(s, AV_LOG_WARNING, "unknown guid "FF_PRI_GUID", expected metadata_guid; "
00521                    "remaining metadata entries ignored\n", FF_ARG_GUID(guid));
00522             break;
00523         }
00524         avio_get_str16le(pb, INT_MAX, key, sizeof(key));
00525         get_tag(s, pb, key, type, length);
00526     }
00527 
00528     ff_metadata_conv(&s->metadata, NULL, ff_asf_metadata_conv);
00529 }
00530 
00535 static int parse_videoinfoheader2(AVFormatContext *s, AVStream *st)
00536 {
00537     WtvContext *wtv = s->priv_data;
00538     AVIOContext *pb = wtv->pb;
00539 
00540     avio_skip(pb, 72);  // picture aspect ratio is unreliable
00541     ff_get_bmp_header(pb, st, NULL);
00542 
00543     return 72 + 40;
00544 }
00545 
00549 static void parse_mpeg1waveformatex(AVStream *st)
00550 {
00551     /* fwHeadLayer */
00552     switch (AV_RL16(st->codec->extradata)) {
00553     case 0x0001 : st->codec->codec_id = AV_CODEC_ID_MP1; break;
00554     case 0x0002 : st->codec->codec_id = AV_CODEC_ID_MP2; break;
00555     case 0x0004 : st->codec->codec_id = AV_CODEC_ID_MP3; break;
00556     }
00557 
00558     st->codec->bit_rate = AV_RL32(st->codec->extradata + 2); /* dwHeadBitrate */
00559 
00560     /* dwHeadMode */
00561     switch (AV_RL16(st->codec->extradata + 6)) {
00562     case 1 :
00563     case 2 :
00564     case 4 : st->codec->channels       = 2;
00565              st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
00566              break;
00567     case 8 : st->codec->channels       = 1;
00568              st->codec->channel_layout = AV_CH_LAYOUT_MONO;
00569              break;
00570     }
00571 }
00572 
00578 static AVStream * new_stream(AVFormatContext *s, AVStream *st, int sid, int codec_type)
00579 {
00580     if (st) {
00581         if (st->codec->extradata) {
00582             av_freep(&st->codec->extradata);
00583             st->codec->extradata_size = 0;
00584         }
00585     } else {
00586         WtvStream *wst = av_mallocz(sizeof(WtvStream));
00587         if (!wst)
00588             return NULL;
00589         st = avformat_new_stream(s, NULL);
00590         if (!st) {
00591             av_free(wst);
00592             return NULL;
00593         }
00594         st->id = sid;
00595         st->priv_data = wst;
00596     }
00597     st->codec->codec_type = codec_type;
00598     st->need_parsing      = AVSTREAM_PARSE_FULL;
00599     avpriv_set_pts_info(st, 64, 1, 10000000);
00600     return st;
00601 }
00602 
00612 static AVStream * parse_media_type(AVFormatContext *s, AVStream *st, int sid,
00613                                    ff_asf_guid mediatype, ff_asf_guid subtype,
00614                                    ff_asf_guid formattype, int size)
00615 {
00616     WtvContext *wtv = s->priv_data;
00617     AVIOContext *pb = wtv->pb;
00618     if (!ff_guidcmp(subtype, ff_mediasubtype_cpfilters_processed) &&
00619         !ff_guidcmp(formattype, ff_format_cpfilters_processed)) {
00620         ff_asf_guid actual_subtype;
00621         ff_asf_guid actual_formattype;
00622 
00623         if (size < 32) {
00624             av_log(s, AV_LOG_WARNING, "format buffer size underflow\n");
00625             avio_skip(pb, size);
00626             return NULL;
00627         }
00628 
00629         avio_skip(pb, size - 32);
00630         ff_get_guid(pb, &actual_subtype);
00631         ff_get_guid(pb, &actual_formattype);
00632         avio_seek(pb, -size, SEEK_CUR);
00633 
00634         st = parse_media_type(s, st, sid, mediatype, actual_subtype, actual_formattype, size - 32);
00635         avio_skip(pb, 32);
00636         return st;
00637     } else if (!ff_guidcmp(mediatype, ff_mediatype_audio)) {
00638         st = new_stream(s, st, sid, AVMEDIA_TYPE_AUDIO);
00639         if (!st)
00640             return NULL;
00641         if (!ff_guidcmp(formattype, ff_format_waveformatex)) {
00642             int ret = ff_get_wav_header(pb, st->codec, size);
00643             if (ret < 0)
00644                 return NULL;
00645         } else {
00646             if (ff_guidcmp(formattype, ff_format_none))
00647                 av_log(s, AV_LOG_WARNING, "unknown formattype:"FF_PRI_GUID"\n", FF_ARG_GUID(formattype));
00648             avio_skip(pb, size);
00649         }
00650 
00651         if (!memcmp(subtype + 4, (const uint8_t[]){FF_MEDIASUBTYPE_BASE_GUID}, 12)) {
00652             st->codec->codec_id = ff_wav_codec_get_id(AV_RL32(subtype), st->codec->bits_per_coded_sample);
00653         } else if (!ff_guidcmp(subtype, mediasubtype_mpeg1payload)) {
00654             if (st->codec->extradata && st->codec->extradata_size >= 22)
00655                 parse_mpeg1waveformatex(st);
00656             else
00657                 av_log(s, AV_LOG_WARNING, "MPEG1WAVEFORMATEX underflow\n");
00658         } else {
00659             st->codec->codec_id = ff_codec_guid_get_id(ff_codec_wav_guids, subtype);
00660             if (st->codec->codec_id == AV_CODEC_ID_NONE)
00661                 av_log(s, AV_LOG_WARNING, "unknown subtype:"FF_PRI_GUID"\n", FF_ARG_GUID(subtype));
00662         }
00663         return st;
00664     } else if (!ff_guidcmp(mediatype, ff_mediatype_video)) {
00665         st = new_stream(s, st, sid, AVMEDIA_TYPE_VIDEO);
00666         if (!st)
00667             return NULL;
00668         if (!ff_guidcmp(formattype, format_videoinfo2)) {
00669             int consumed = parse_videoinfoheader2(s, st);
00670             avio_skip(pb, FFMAX(size - consumed, 0));
00671         } else if (!ff_guidcmp(formattype, ff_format_mpeg2_video)) {
00672             int consumed = parse_videoinfoheader2(s, st);
00673             avio_skip(pb, FFMAX(size - consumed, 0));
00674         } else {
00675             if (ff_guidcmp(formattype, ff_format_none))
00676                 av_log(s, AV_LOG_WARNING, "unknown formattype:"FF_PRI_GUID"\n", FF_ARG_GUID(formattype));
00677             avio_skip(pb, size);
00678         }
00679 
00680         if (!memcmp(subtype + 4, (const uint8_t[]){FF_MEDIASUBTYPE_BASE_GUID}, 12)) {
00681             st->codec->codec_id = ff_codec_get_id(ff_codec_bmp_tags, AV_RL32(subtype));
00682         } else {
00683             st->codec->codec_id = ff_codec_guid_get_id(ff_video_guids, subtype);
00684         }
00685         if (st->codec->codec_id == AV_CODEC_ID_NONE)
00686             av_log(s, AV_LOG_WARNING, "unknown subtype:"FF_PRI_GUID"\n", FF_ARG_GUID(subtype));
00687         return st;
00688     } else if (!ff_guidcmp(mediatype, mediatype_mpeg2_pes) &&
00689                !ff_guidcmp(subtype, mediasubtype_dvb_subtitle)) {
00690         st = new_stream(s, st, sid, AVMEDIA_TYPE_SUBTITLE);
00691         if (!st)
00692             return NULL;
00693         if (ff_guidcmp(formattype, ff_format_none))
00694             av_log(s, AV_LOG_WARNING, "unknown formattype:"FF_PRI_GUID"\n", FF_ARG_GUID(formattype));
00695         avio_skip(pb, size);
00696         st->codec->codec_id = AV_CODEC_ID_DVB_SUBTITLE;
00697         return st;
00698     } else if (!ff_guidcmp(mediatype, mediatype_mstvcaption) &&
00699                (!ff_guidcmp(subtype, mediasubtype_teletext) || !ff_guidcmp(subtype, mediasubtype_dtvccdata))) {
00700         st = new_stream(s, st, sid, AVMEDIA_TYPE_SUBTITLE);
00701         if (!st)
00702             return NULL;
00703         if (ff_guidcmp(formattype, ff_format_none))
00704             av_log(s, AV_LOG_WARNING, "unknown formattype:"FF_PRI_GUID"\n", FF_ARG_GUID(formattype));
00705         avio_skip(pb, size);
00706         st->codec->codec_id = !ff_guidcmp(subtype, mediasubtype_teletext) ? AV_CODEC_ID_DVB_TELETEXT : AV_CODEC_ID_EIA_608;
00707         return st;
00708     } else if (!ff_guidcmp(mediatype, mediatype_mpeg2_sections) &&
00709                !ff_guidcmp(subtype, mediasubtype_mpeg2_sections)) {
00710         if (ff_guidcmp(formattype, ff_format_none))
00711             av_log(s, AV_LOG_WARNING, "unknown formattype:"FF_PRI_GUID"\n", FF_ARG_GUID(formattype));
00712         avio_skip(pb, size);
00713         return NULL;
00714     }
00715 
00716     av_log(s, AV_LOG_WARNING, "unknown media type, mediatype:"FF_PRI_GUID
00717                               ", subtype:"FF_PRI_GUID", formattype:"FF_PRI_GUID"\n",
00718                               FF_ARG_GUID(mediatype), FF_ARG_GUID(subtype), FF_ARG_GUID(formattype));
00719     avio_skip(pb, size);
00720     return NULL;
00721 }
00722 
00723 enum {
00724     SEEK_TO_DATA = 0,
00725     SEEK_TO_PTS,
00726 };
00727 
00735 static int parse_chunks(AVFormatContext *s, int mode, int64_t seekts, int *len_ptr)
00736 {
00737     WtvContext *wtv = s->priv_data;
00738     AVIOContext *pb = wtv->pb;
00739     while (!url_feof(pb)) {
00740         ff_asf_guid g;
00741         int len, sid, consumed;
00742 
00743         ff_get_guid(pb, &g);
00744         len = avio_rl32(pb);
00745         if (len < 32)
00746             break;
00747         sid = avio_rl32(pb) & 0x7FFF;
00748         avio_skip(pb, 8);
00749         consumed = 32;
00750 
00751         if (!ff_guidcmp(g, ff_SBE2_STREAM_DESC_EVENT)) {
00752             if (ff_find_stream_index(s, sid) < 0) {
00753                 ff_asf_guid mediatype, subtype, formattype;
00754                 int size;
00755                 avio_skip(pb, 28);
00756                 ff_get_guid(pb, &mediatype);
00757                 ff_get_guid(pb, &subtype);
00758                 avio_skip(pb, 12);
00759                 ff_get_guid(pb, &formattype);
00760                 size = avio_rl32(pb);
00761                 parse_media_type(s, 0, sid, mediatype, subtype, formattype, size);
00762                 consumed += 92 + size;
00763             }
00764         } else if (!ff_guidcmp(g, ff_stream2_guid)) {
00765             int stream_index = ff_find_stream_index(s, sid);
00766             if (stream_index >= 0 && s->streams[stream_index]->priv_data && !((WtvStream*)s->streams[stream_index]->priv_data)->seen_data) {
00767                 ff_asf_guid mediatype, subtype, formattype;
00768                 int size;
00769                 avio_skip(pb, 12);
00770                 ff_get_guid(pb, &mediatype);
00771                 ff_get_guid(pb, &subtype);
00772                 avio_skip(pb, 12);
00773                 ff_get_guid(pb, &formattype);
00774                 size = avio_rl32(pb);
00775                 parse_media_type(s, s->streams[stream_index], sid, mediatype, subtype, formattype, size);
00776                 consumed += 76 + size;
00777             }
00778         } else if (!ff_guidcmp(g, EVENTID_AudioDescriptorSpanningEvent) ||
00779                    !ff_guidcmp(g, EVENTID_CtxADescriptorSpanningEvent) ||
00780                    !ff_guidcmp(g, EVENTID_CSDescriptorSpanningEvent) ||
00781                    !ff_guidcmp(g, EVENTID_StreamIDSpanningEvent) ||
00782                    !ff_guidcmp(g, EVENTID_SubtitleSpanningEvent) ||
00783                    !ff_guidcmp(g, EVENTID_TeletextSpanningEvent)) {
00784             int stream_index = ff_find_stream_index(s, sid);
00785             if (stream_index >= 0) {
00786                 AVStream *st = s->streams[stream_index];
00787                 uint8_t buf[258];
00788                 const uint8_t *pbuf = buf;
00789                 int buf_size;
00790 
00791                 avio_skip(pb, 8);
00792                 consumed += 8;
00793                 if (!ff_guidcmp(g, EVENTID_CtxADescriptorSpanningEvent) ||
00794                     !ff_guidcmp(g, EVENTID_CSDescriptorSpanningEvent)) {
00795                     avio_skip(pb, 6);
00796                     consumed += 6;
00797                 }
00798 
00799                 buf_size = FFMIN(len - consumed, sizeof(buf));
00800                 avio_read(pb, buf, buf_size);
00801                 consumed += buf_size;
00802                 ff_parse_mpeg2_descriptor(s, st, 0, &pbuf, buf + buf_size, NULL, 0, 0, NULL);
00803             }
00804         } else if (!ff_guidcmp(g, EVENTID_AudioTypeSpanningEvent)) {
00805             int stream_index = ff_find_stream_index(s, sid);
00806             if (stream_index >= 0) {
00807                 AVStream *st = s->streams[stream_index];
00808                 int audio_type;
00809                 avio_skip(pb, 8);
00810                 audio_type = avio_r8(pb);
00811                 if (audio_type == 2)
00812                     st->disposition |= AV_DISPOSITION_HEARING_IMPAIRED;
00813                 else if (audio_type == 3)
00814                     st->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED;
00815                 consumed += 9;
00816             }
00817         } else if (!ff_guidcmp(g, EVENTID_DVBScramblingControlSpanningEvent)) {
00818             int stream_index = ff_find_stream_index(s, sid);
00819             if (stream_index >= 0) {
00820                 avio_skip(pb, 12);
00821                 if (avio_rl32(pb))
00822                     av_log(s, AV_LOG_WARNING, "DVB scrambled stream detected (st:%d), decoding will likely fail\n", stream_index);
00823                 consumed += 16;
00824             }
00825         } else if (!ff_guidcmp(g, EVENTID_LanguageSpanningEvent)) {
00826             int stream_index = ff_find_stream_index(s, sid);
00827             if (stream_index >= 0) {
00828                 AVStream *st = s->streams[stream_index];
00829                 uint8_t language[4];
00830                 avio_skip(pb, 12);
00831                 avio_read(pb, language, 3);
00832                 if (language[0]) {
00833                     language[3] = 0;
00834                     av_dict_set(&st->metadata, "language", language, 0);
00835                     if (!strcmp(language, "nar") || !strcmp(language, "NAR"))
00836                         st->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED;
00837                 }
00838                 consumed += 15;
00839             }
00840         } else if (!ff_guidcmp(g, ff_timestamp_guid)) {
00841             int stream_index = ff_find_stream_index(s, sid);
00842             if (stream_index >= 0) {
00843                 avio_skip(pb, 8);
00844                 wtv->pts = avio_rl64(pb);
00845                 consumed += 16;
00846                 if (wtv->pts == -1)
00847                     wtv->pts = AV_NOPTS_VALUE;
00848                 else {
00849                     wtv->last_valid_pts = wtv->pts;
00850                     if (wtv->epoch == AV_NOPTS_VALUE || wtv->pts < wtv->epoch)
00851                         wtv->epoch = wtv->pts;
00852                 if (mode == SEEK_TO_PTS && wtv->pts >= seekts) {
00853                     avio_skip(pb, WTV_PAD8(len) - consumed);
00854                     return 0;
00855                 }
00856                 }
00857             }
00858         } else if (!ff_guidcmp(g, ff_data_guid)) {
00859             int stream_index = ff_find_stream_index(s, sid);
00860             if (mode == SEEK_TO_DATA && stream_index >= 0 && len > 32 && s->streams[stream_index]->priv_data) {
00861                 WtvStream *wst = s->streams[stream_index]->priv_data;
00862                 wst->seen_data = 1;
00863                 if (len_ptr) {
00864                     *len_ptr = len;
00865                 }
00866                 return stream_index;
00867             }
00868         } else if (!ff_guidcmp(g, /* DSATTRIB_WMDRMProtectionInfo */ (const ff_asf_guid){0x83,0x95,0x74,0x40,0x9D,0x6B,0xEC,0x4E,0xB4,0x3C,0x67,0xA1,0x80,0x1E,0x1A,0x9B})) {
00869             int stream_index = ff_find_stream_index(s, sid);
00870             if (stream_index >= 0)
00871                 av_log(s, AV_LOG_WARNING, "encrypted stream detected (st:%d), decoding will likely fail\n", stream_index);
00872         } else if (
00873             !ff_guidcmp(g, /* DSATTRIB_CAPTURE_STREAMTIME */ (const ff_asf_guid){0x14,0x56,0x1A,0x0C,0xCD,0x30,0x40,0x4F,0xBC,0xBF,0xD0,0x3E,0x52,0x30,0x62,0x07}) ||
00874             !ff_guidcmp(g, /* DSATTRIB_PBDATAG_ATTRIBUTE */ (const ff_asf_guid){0x79,0x66,0xB5,0xE0,0xB9,0x12,0xCC,0x43,0xB7,0xDF,0x57,0x8C,0xAA,0x5A,0x7B,0x63}) ||
00875             !ff_guidcmp(g, /* DSATTRIB_PicSampleSeq */ (const ff_asf_guid){0x02,0xAE,0x5B,0x2F,0x8F,0x7B,0x60,0x4F,0x82,0xD6,0xE4,0xEA,0x2F,0x1F,0x4C,0x99}) ||
00876             !ff_guidcmp(g, /* DSATTRIB_TRANSPORT_PROPERTIES */ ff_DSATTRIB_TRANSPORT_PROPERTIES) ||
00877             !ff_guidcmp(g, /* dvr_ms_vid_frame_rep_data */ (const ff_asf_guid){0xCC,0x32,0x64,0xDD,0x29,0xE2,0xDB,0x40,0x80,0xF6,0xD2,0x63,0x28,0xD2,0x76,0x1F}) ||
00878             !ff_guidcmp(g, /* EVENTID_ChannelChangeSpanningEvent */ (const ff_asf_guid){0xE5,0xC5,0x67,0x90,0x5C,0x4C,0x05,0x42,0x86,0xC8,0x7A,0xFE,0x20,0xFE,0x1E,0xFA}) ||
00879             !ff_guidcmp(g, /* EVENTID_ChannelInfoSpanningEvent */ (const ff_asf_guid){0x80,0x6D,0xF3,0x41,0x32,0x41,0xC2,0x4C,0xB1,0x21,0x01,0xA4,0x32,0x19,0xD8,0x1B}) ||
00880             !ff_guidcmp(g, /* EVENTID_ChannelTypeSpanningEvent */ (const ff_asf_guid){0x51,0x1D,0xAB,0x72,0xD2,0x87,0x9B,0x48,0xBA,0x11,0x0E,0x08,0xDC,0x21,0x02,0x43}) ||
00881             !ff_guidcmp(g, /* EVENTID_PIDListSpanningEvent */ (const ff_asf_guid){0x65,0x8F,0xFC,0x47,0xBB,0xE2,0x34,0x46,0x9C,0xEF,0xFD,0xBF,0xE6,0x26,0x1D,0x5C}) ||
00882             !ff_guidcmp(g, /* EVENTID_SignalAndServiceStatusSpanningEvent */ (const ff_asf_guid){0xCB,0xC5,0x68,0x80,0x04,0x3C,0x2B,0x49,0xB4,0x7D,0x03,0x08,0x82,0x0D,0xCE,0x51}) ||
00883             !ff_guidcmp(g, /* EVENTID_StreamTypeSpanningEvent */ (const ff_asf_guid){0xBC,0x2E,0xAF,0x82,0xA6,0x30,0x64,0x42,0xA8,0x0B,0xAD,0x2E,0x13,0x72,0xAC,0x60}) ||
00884             !ff_guidcmp(g, (const ff_asf_guid){0x1E,0xBE,0xC3,0xC5,0x43,0x92,0xDC,0x11,0x85,0xE5,0x00,0x12,0x3F,0x6F,0x73,0xB9}) ||
00885             !ff_guidcmp(g, (const ff_asf_guid){0x3B,0x86,0xA2,0xB1,0xEB,0x1E,0xC3,0x44,0x8C,0x88,0x1C,0xA3,0xFF,0xE3,0xE7,0x6A}) ||
00886             !ff_guidcmp(g, (const ff_asf_guid){0x4E,0x7F,0x4C,0x5B,0xC4,0xD0,0x38,0x4B,0xA8,0x3E,0x21,0x7F,0x7B,0xBF,0x52,0xE7}) ||
00887             !ff_guidcmp(g, (const ff_asf_guid){0x63,0x36,0xEB,0xFE,0xA1,0x7E,0xD9,0x11,0x83,0x08,0x00,0x07,0xE9,0x5E,0xAD,0x8D}) ||
00888             !ff_guidcmp(g, (const ff_asf_guid){0x70,0xE9,0xF1,0xF8,0x89,0xA4,0x4C,0x4D,0x83,0x73,0xB8,0x12,0xE0,0xD5,0xF8,0x1E}) ||
00889             !ff_guidcmp(g, ff_index_guid) ||
00890             !ff_guidcmp(g, ff_sync_guid) ||
00891             !ff_guidcmp(g, ff_stream1_guid) ||
00892             !ff_guidcmp(g, (const ff_asf_guid){0xF7,0x10,0x02,0xB9,0xEE,0x7C,0xED,0x4E,0xBD,0x7F,0x05,0x40,0x35,0x86,0x18,0xA1})) {
00893             //ignore known guids
00894         } else
00895             av_log(s, AV_LOG_WARNING, "unsupported chunk:"FF_PRI_GUID"\n", FF_ARG_GUID(g));
00896 
00897         avio_skip(pb, WTV_PAD8(len) - consumed);
00898     }
00899     return AVERROR_EOF;
00900 }
00901 
00902 static int read_header(AVFormatContext *s)
00903 {
00904     WtvContext *wtv = s->priv_data;
00905     int root_sector, root_size;
00906     uint8_t root[WTV_SECTOR_SIZE];
00907     AVIOContext *pb;
00908     int64_t timeline_pos;
00909     int ret;
00910 
00911     wtv->epoch          =
00912     wtv->pts            =
00913     wtv->last_valid_pts = AV_NOPTS_VALUE;
00914 
00915     /* read root directory sector */
00916     avio_skip(s->pb, 0x30);
00917     root_size = avio_rl32(s->pb);
00918     if (root_size > sizeof(root)) {
00919         av_log(s, AV_LOG_ERROR, "root directory size exceeds sector size\n");
00920         return AVERROR_INVALIDDATA;
00921     }
00922     avio_skip(s->pb, 4);
00923     root_sector = avio_rl32(s->pb);
00924 
00925     avio_seek(s->pb, root_sector << WTV_SECTOR_BITS, SEEK_SET);
00926     root_size = avio_read(s->pb, root, root_size);
00927     if (root_size < 0)
00928         return AVERROR_INVALIDDATA;
00929 
00930     /* parse chunks up until first data chunk */
00931     wtv->pb = wtvfile_open(s, root, root_size, ff_timeline_le16);
00932     if (!wtv->pb) {
00933         av_log(s, AV_LOG_ERROR, "timeline data missing\n");
00934         return AVERROR_INVALIDDATA;
00935     }
00936 
00937     ret = parse_chunks(s, SEEK_TO_DATA, 0, 0);
00938     if (ret < 0)
00939         return ret;
00940     avio_seek(wtv->pb, -32, SEEK_CUR);
00941 
00942     timeline_pos = avio_tell(s->pb); // save before opening another file
00943 
00944     /* read metadata */
00945     pb = wtvfile_open(s, root, root_size, ff_table_0_entries_legacy_attrib_le16);
00946     if (pb) {
00947         parse_legacy_attrib(s, pb);
00948         wtvfile_close(pb);
00949     }
00950 
00951     /* read seek index */
00952     if (s->nb_streams) {
00953         AVStream *st = s->streams[0];
00954         pb = wtvfile_open(s, root, root_size, ff_table_0_entries_time_le16);
00955         if (pb) {
00956             while(1) {
00957                 uint64_t timestamp = avio_rl64(pb);
00958                 uint64_t frame_nb  = avio_rl64(pb);
00959                 if (url_feof(pb))
00960                     break;
00961                 ff_add_index_entry(&wtv->index_entries, &wtv->nb_index_entries, &wtv->index_entries_allocated_size,
00962                                    0, timestamp, frame_nb, 0, AVINDEX_KEYFRAME);
00963             }
00964             wtvfile_close(pb);
00965 
00966             if (wtv->nb_index_entries) {
00967                 pb = wtvfile_open(s, root, root_size, ff_timeline_table_0_entries_Events_le16);
00968                 if (pb) {
00969                     int i;
00970                     while (1) {
00971                         uint64_t frame_nb = avio_rl64(pb);
00972                         uint64_t position = avio_rl64(pb);
00973                         if (url_feof(pb))
00974                             break;
00975                         for (i = wtv->nb_index_entries - 1; i >= 0; i--) {
00976                             AVIndexEntry *e = wtv->index_entries + i;
00977                             if (frame_nb > e->size)
00978                                 break;
00979                             if (position > e->pos)
00980                                 e->pos = position;
00981                         }
00982                     }
00983                     wtvfile_close(pb);
00984                     st->duration = wtv->index_entries[wtv->nb_index_entries - 1].timestamp;
00985                 }
00986             }
00987         }
00988     }
00989 
00990     avio_seek(s->pb, timeline_pos, SEEK_SET);
00991     return 0;
00992 }
00993 
00994 static int read_packet(AVFormatContext *s, AVPacket *pkt)
00995 {
00996     WtvContext *wtv = s->priv_data;
00997     AVIOContext *pb = wtv->pb;
00998     int stream_index, len, ret;
00999 
01000     stream_index = parse_chunks(s, SEEK_TO_DATA, 0, &len);
01001     if (stream_index < 0)
01002         return stream_index;
01003 
01004     ret = av_get_packet(pb, pkt, len - 32);
01005     if (ret < 0)
01006         return ret;
01007     pkt->stream_index = stream_index;
01008     pkt->pts          = wtv->pts;
01009     avio_skip(pb, WTV_PAD8(len) - len);
01010     return 0;
01011 }
01012 
01013 static int read_seek(AVFormatContext *s, int stream_index,
01014                      int64_t ts, int flags)
01015 {
01016     WtvContext *wtv = s->priv_data;
01017     AVIOContext *pb = wtv->pb;
01018     AVStream *st = s->streams[0];
01019     int64_t ts_relative;
01020     int i;
01021 
01022     if ((flags & AVSEEK_FLAG_FRAME) || (flags & AVSEEK_FLAG_BYTE))
01023         return AVERROR(ENOSYS);
01024 
01025     /* timestamp adjustment is required because wtv->pts values are absolute,
01026      * whereas AVIndexEntry->timestamp values are relative to epoch. */
01027     ts_relative = ts;
01028     if (wtv->epoch != AV_NOPTS_VALUE)
01029         ts_relative -= wtv->epoch;
01030 
01031     i = ff_index_search_timestamp(wtv->index_entries, wtv->nb_index_entries, ts_relative, flags);
01032     if (i < 0) {
01033         if (wtv->last_valid_pts == AV_NOPTS_VALUE || ts < wtv->last_valid_pts) {
01034             if (avio_seek(pb, 0, SEEK_SET) < 0)
01035                 return -1;
01036         } else if (st->duration != AV_NOPTS_VALUE && ts_relative > st->duration && wtv->nb_index_entries) {
01037             if (avio_seek(pb, wtv->index_entries[wtv->nb_index_entries - 1].pos, SEEK_SET) < 0)
01038                 return -1;
01039         }
01040         if (parse_chunks(s, SEEK_TO_PTS, ts, 0) < 0)
01041             return AVERROR(ERANGE);
01042         return 0;
01043     }
01044     if (avio_seek(pb, wtv->index_entries[i].pos, SEEK_SET) < 0)
01045         return -1;
01046     wtv->pts = wtv->index_entries[i].timestamp;
01047     if (wtv->epoch != AV_NOPTS_VALUE)
01048         wtv->pts += wtv->epoch;
01049     wtv->last_valid_pts = wtv->pts;
01050     return 0;
01051 }
01052 
01053 static int read_close(AVFormatContext *s)
01054 {
01055     WtvContext *wtv = s->priv_data;
01056     av_freep(&wtv->index_entries);
01057     wtvfile_close(wtv->pb);
01058     return 0;
01059 }
01060 
01061 AVInputFormat ff_wtv_demuxer = {
01062     .name           = "wtv",
01063     .long_name      = NULL_IF_CONFIG_SMALL("Windows Television (WTV)"),
01064     .priv_data_size = sizeof(WtvContext),
01065     .read_probe     = read_probe,
01066     .read_header    = read_header,
01067     .read_packet    = read_packet,
01068     .read_seek      = read_seek,
01069     .read_close     = read_close,
01070     .flags          = AVFMT_SHOW_IDS,
01071 };