FFmpeg: libavformat/bethsoftvid.c Source File

00001 /*
00002  * Bethsoft VID format Demuxer
00003  * Copyright (c) 2007 Nicholas Tung
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 
00030 #include "libavutil/channel_layout.h"
00031 #include "libavutil/intreadwrite.h"
00032 #include "avformat.h"
00033 #include "internal.h"
00034 #include "libavcodec/bethsoftvideo.h"
00035 
00036 #define BVID_PALETTE_SIZE 3 * 256
00037 
00038 #define DEFAULT_SAMPLE_RATE 11111
00039 
00040 typedef struct BVID_DemuxContext
00041 {
00042     int nframes;
00043     int sample_rate;        
00044     int width;              
00045     int height;             
00049     int bethsoft_global_delay;
00050     int video_index;        
00051     int audio_index;        
00052     uint8_t *palette;
00053 
00054     int is_finished;
00055 
00056 } BVID_DemuxContext;
00057 
00058 static int vid_probe(AVProbeData *p)
00059 {
00060     // little endian VID tag, file starts with "VID\0"
00061     if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))
00062         return 0;
00063 
00064     return AVPROBE_SCORE_MAX;
00065 }
00066 
00067 static int vid_read_header(AVFormatContext *s)
00068 {
00069     BVID_DemuxContext *vid = s->priv_data;
00070     AVIOContext *pb = s->pb;
00071 
00072     /* load main header. Contents:
00073     *    bytes: 'V' 'I' 'D'
00074     *    int16s: always_512, nframes, width, height, delay, always_14
00075     */
00076     avio_skip(pb, 5);
00077     vid->nframes = avio_rl16(pb);
00078     vid->width   = avio_rl16(pb);
00079     vid->height  = avio_rl16(pb);
00080     vid->bethsoft_global_delay = avio_rl16(pb);
00081     avio_rl16(pb);
00082 
00083     // wait until the first packet to create each stream
00084     vid->video_index = -1;
00085     vid->audio_index = -1;
00086     vid->sample_rate = DEFAULT_SAMPLE_RATE;
00087     s->ctx_flags |= AVFMTCTX_NOHEADER;
00088 
00089     return 0;
00090 }
00091 
00092 #define BUFFER_PADDING_SIZE 1000
00093 static int read_frame(BVID_DemuxContext *vid, AVIOContext *pb, AVPacket *pkt,
00094                       uint8_t block_type, AVFormatContext *s)
00095 {
00096     uint8_t * vidbuf_start = NULL;
00097     int vidbuf_nbytes = 0;
00098     int code;
00099     int bytes_copied = 0;
00100     int position, duration, npixels;
00101     unsigned int vidbuf_capacity;
00102     int ret = 0;
00103     AVStream *st;
00104 
00105     if (vid->video_index < 0) {
00106         st = avformat_new_stream(s, NULL);
00107         if (!st)
00108             return AVERROR(ENOMEM);
00109         vid->video_index = st->index;
00110         if (vid->audio_index < 0) {
00111             av_log_ask_for_sample(s, "No audio packet before first video "
00112                                   "packet. Using default video time base.\n");
00113         }
00114         avpriv_set_pts_info(st, 64, 185, vid->sample_rate);
00115         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00116         st->codec->codec_id   = AV_CODEC_ID_BETHSOFTVID;
00117         st->codec->width      = vid->width;
00118         st->codec->height     = vid->height;
00119     }
00120     st      = s->streams[vid->video_index];
00121     npixels = st->codec->width * st->codec->height;
00122 
00123     vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);
00124     if(!vidbuf_start)
00125         return AVERROR(ENOMEM);
00126 
00127     // save the file position for the packet, include block type
00128     position = avio_tell(pb) - 1;
00129 
00130     vidbuf_start[vidbuf_nbytes++] = block_type;
00131 
00132     // get the current packet duration
00133     duration = vid->bethsoft_global_delay + avio_rl16(pb);
00134 
00135     // set the y offset if it exists (decoder header data should be in data section)
00136     if(block_type == VIDEO_YOFF_P_FRAME){
00137         if (avio_read(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2) {
00138             ret = AVERROR(EIO);
00139             goto fail;
00140         }
00141         vidbuf_nbytes += 2;
00142     }
00143 
00144     do{
00145         vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);
00146         if(!vidbuf_start)
00147             return AVERROR(ENOMEM);
00148 
00149         code = avio_r8(pb);
00150         vidbuf_start[vidbuf_nbytes++] = code;
00151 
00152         if(code >= 0x80){ // rle sequence
00153             if(block_type == VIDEO_I_FRAME)
00154                 vidbuf_start[vidbuf_nbytes++] = avio_r8(pb);
00155         } else if(code){ // plain sequence
00156             if (avio_read(pb, &vidbuf_start[vidbuf_nbytes], code) != code) {
00157                 ret = AVERROR(EIO);
00158                 goto fail;
00159             }
00160             vidbuf_nbytes += code;
00161         }
00162         bytes_copied += code & 0x7F;
00163         if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied
00164             // may contain a 0 byte even if read all pixels
00165             if(avio_r8(pb))
00166                 avio_seek(pb, -1, SEEK_CUR);
00167             break;
00168         }
00169         if (bytes_copied > npixels) {
00170             ret = AVERROR_INVALIDDATA;
00171             goto fail;
00172         }
00173     } while(code);
00174 
00175     // copy data into packet
00176     if ((ret = av_new_packet(pkt, vidbuf_nbytes)) < 0)
00177         goto fail;
00178     memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
00179     av_free(vidbuf_start);
00180 
00181     pkt->pos = position;
00182     pkt->stream_index = vid->video_index;
00183     pkt->duration = duration;
00184     if (block_type == VIDEO_I_FRAME)
00185         pkt->flags |= AV_PKT_FLAG_KEY;
00186 
00187     /* if there is a new palette available, add it to packet side data */
00188     if (vid->palette) {
00189         uint8_t *pdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
00190                                                  BVID_PALETTE_SIZE);
00191         if (pdata)
00192             memcpy(pdata, vid->palette, BVID_PALETTE_SIZE);
00193         av_freep(&vid->palette);
00194     }
00195 
00196     vid->nframes--;  // used to check if all the frames were read
00197     return 0;
00198 fail:
00199     av_free(vidbuf_start);
00200     return ret;
00201 }
00202 
00203 static int vid_read_packet(AVFormatContext *s,
00204                            AVPacket *pkt)
00205 {
00206     BVID_DemuxContext *vid = s->priv_data;
00207     AVIOContext *pb = s->pb;
00208     unsigned char block_type;
00209     int audio_length;
00210     int ret_value;
00211 
00212     if(vid->is_finished || url_feof(pb))
00213         return AVERROR_EOF;
00214 
00215     block_type = avio_r8(pb);
00216     switch(block_type){
00217         case PALETTE_BLOCK:
00218             if (vid->palette) {
00219                 av_log(s, AV_LOG_WARNING, "discarding unused palette\n");
00220                 av_freep(&vid->palette);
00221             }
00222             vid->palette = av_malloc(BVID_PALETTE_SIZE);
00223             if (!vid->palette)
00224                 return AVERROR(ENOMEM);
00225             if (avio_read(pb, vid->palette, BVID_PALETTE_SIZE) != BVID_PALETTE_SIZE) {
00226                 av_freep(&vid->palette);
00227                 return AVERROR(EIO);
00228             }
00229             return vid_read_packet(s, pkt);
00230 
00231         case FIRST_AUDIO_BLOCK:
00232             avio_rl16(pb);
00233             // soundblaster DAC used for sample rate, as on specification page (link above)
00234             vid->sample_rate = 1000000 / (256 - avio_r8(pb));
00235         case AUDIO_BLOCK:
00236             if (vid->audio_index < 0) {
00237                 AVStream *st = avformat_new_stream(s, NULL);
00238                 if (!st)
00239                     return AVERROR(ENOMEM);
00240                 vid->audio_index                 = st->index;
00241                 st->codec->codec_type            = AVMEDIA_TYPE_AUDIO;
00242                 st->codec->codec_id              = AV_CODEC_ID_PCM_U8;
00243                 st->codec->channels              = 1;
00244                 st->codec->channel_layout        = AV_CH_LAYOUT_MONO;
00245                 st->codec->bits_per_coded_sample = 8;
00246                 st->codec->sample_rate           = vid->sample_rate;
00247                 st->codec->bit_rate              = 8 * st->codec->sample_rate;
00248                 st->start_time                   = 0;
00249                 avpriv_set_pts_info(st, 64, 1, vid->sample_rate);
00250             }
00251             audio_length = avio_rl16(pb);
00252             if ((ret_value = av_get_packet(pb, pkt, audio_length)) != audio_length) {
00253                 if (ret_value < 0)
00254                     return ret_value;
00255                 av_log(s, AV_LOG_ERROR, "incomplete audio block\n");
00256                 return AVERROR(EIO);
00257             }
00258             pkt->stream_index = vid->audio_index;
00259             pkt->duration     = audio_length;
00260             pkt->flags |= AV_PKT_FLAG_KEY;
00261             return 0;
00262 
00263         case VIDEO_P_FRAME:
00264         case VIDEO_YOFF_P_FRAME:
00265         case VIDEO_I_FRAME:
00266             return read_frame(vid, pb, pkt, block_type, s);
00267 
00268         case EOF_BLOCK:
00269             if(vid->nframes != 0)
00270                 av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
00271             vid->is_finished = 1;
00272             return AVERROR(EIO);
00273         default:
00274             av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",
00275                    block_type, block_type, block_type);
00276             return AVERROR_INVALIDDATA;
00277     }
00278 }
00279 
00280 static int vid_read_close(AVFormatContext *s)
00281 {
00282     BVID_DemuxContext *vid = s->priv_data;
00283     av_freep(&vid->palette);
00284     return 0;
00285 }
00286 
00287 AVInputFormat ff_bethsoftvid_demuxer = {
00288     .name           = "bethsoftvid",
00289     .long_name      = NULL_IF_CONFIG_SMALL("Bethesda Softworks VID"),
00290     .priv_data_size = sizeof(BVID_DemuxContext),
00291     .read_probe     = vid_probe,
00292     .read_header    = vid_read_header,
00293     .read_packet    = vid_read_packet,
00294     .read_close     = vid_read_close,
00295 };