FFmpeg: libavformat/westwood.c Source File

00001 /*
00002  * Westwood Studios Multimedia Formats Demuxer (VQA, AUD)
00003  * Copyright (c) 2003 The ffmpeg Project
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 
00036 #include "libavutil/intreadwrite.h"
00037 #include "avformat.h"
00038 
00039 #define AUD_HEADER_SIZE 12
00040 #define AUD_CHUNK_PREAMBLE_SIZE 8
00041 #define AUD_CHUNK_SIGNATURE 0x0000DEAF
00042 
00043 #define FORM_TAG MKBETAG('F', 'O', 'R', 'M')
00044 #define WVQA_TAG MKBETAG('W', 'V', 'Q', 'A')
00045 #define VQHD_TAG MKBETAG('V', 'Q', 'H', 'D')
00046 #define FINF_TAG MKBETAG('F', 'I', 'N', 'F')
00047 #define SND0_TAG MKBETAG('S', 'N', 'D', '0')
00048 #define SND1_TAG MKBETAG('S', 'N', 'D', '1')
00049 #define SND2_TAG MKBETAG('S', 'N', 'D', '2')
00050 #define VQFR_TAG MKBETAG('V', 'Q', 'F', 'R')
00051 
00052 /* don't know what these tags are for, but acknowledge their existence */
00053 #define CINF_TAG MKBETAG('C', 'I', 'N', 'F')
00054 #define CINH_TAG MKBETAG('C', 'I', 'N', 'H')
00055 #define CIND_TAG MKBETAG('C', 'I', 'N', 'D')
00056 #define PINF_TAG MKBETAG('P', 'I', 'N', 'F')
00057 #define PINH_TAG MKBETAG('P', 'I', 'N', 'H')
00058 #define PIND_TAG MKBETAG('P', 'I', 'N', 'D')
00059 #define CMDS_TAG MKBETAG('C', 'M', 'D', 'S')
00060 
00061 #define VQA_HEADER_SIZE 0x2A
00062 #define VQA_FRAMERATE 15
00063 #define VQA_PREAMBLE_SIZE 8
00064 
00065 typedef struct WsAudDemuxContext {
00066     int audio_samplerate;
00067     int audio_channels;
00068     int audio_bits;
00069     enum CodecID audio_type;
00070     int audio_stream_index;
00071     int64_t audio_frame_counter;
00072 } WsAudDemuxContext;
00073 
00074 typedef struct WsVqaDemuxContext {
00075     int audio_samplerate;
00076     int audio_channels;
00077     int audio_bits;
00078 
00079     int audio_stream_index;
00080     int video_stream_index;
00081 
00082     int64_t audio_frame_counter;
00083 } WsVqaDemuxContext;
00084 
00085 static int wsaud_probe(AVProbeData *p)
00086 {
00087     int field;
00088 
00089     /* Probabilistic content detection strategy: There is no file signature
00090      * so perform sanity checks on various header parameters:
00091      *   8000 <= sample rate (16 bits) <= 48000  ==> 40001 acceptable numbers
00092      *   flags <= 0x03 (2 LSBs are used)         ==> 4 acceptable numbers
00093      *   compression type (8 bits) = 1 or 99     ==> 2 acceptable numbers
00094      *   first audio chunk signature (32 bits)   ==> 1 acceptable number
00095      * The number space contains 2^64 numbers. There are 40001 * 4 * 2 * 1 =
00096      * 320008 acceptable number combinations.
00097      */
00098 
00099     if (p->buf_size < AUD_HEADER_SIZE + AUD_CHUNK_PREAMBLE_SIZE)
00100         return 0;
00101 
00102     /* check sample rate */
00103     field = AV_RL16(&p->buf[0]);
00104     if ((field < 8000) || (field > 48000))
00105         return 0;
00106 
00107     /* enforce the rule that the top 6 bits of this flags field are reserved (0);
00108      * this might not be true, but enforce it until deemed unnecessary */
00109     if (p->buf[10] & 0xFC)
00110         return 0;
00111 
00112     /* note: only check for WS IMA (type 99) right now since there is no
00113      * support for type 1 */
00114     if (p->buf[11] != 99)
00115         return 0;
00116 
00117     /* read ahead to the first audio chunk and validate the first header signature */
00118     if (AV_RL32(&p->buf[16]) != AUD_CHUNK_SIGNATURE)
00119         return 0;
00120 
00121     /* return 1/2 certainty since this file check is a little sketchy */
00122     return AVPROBE_SCORE_MAX / 2;
00123 }
00124 
00125 static int wsaud_read_header(AVFormatContext *s,
00126                              AVFormatParameters *ap)
00127 {
00128     WsAudDemuxContext *wsaud = s->priv_data;
00129     ByteIOContext *pb = s->pb;
00130     AVStream *st;
00131     unsigned char header[AUD_HEADER_SIZE];
00132 
00133     if (get_buffer(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE)
00134         return AVERROR(EIO);
00135     wsaud->audio_samplerate = AV_RL16(&header[0]);
00136     if (header[11] == 99)
00137         wsaud->audio_type = CODEC_ID_ADPCM_IMA_WS;
00138     else
00139         return AVERROR_INVALIDDATA;
00140 
00141     /* flag 0 indicates stereo */
00142     wsaud->audio_channels = (header[10] & 0x1) + 1;
00143     /* flag 1 indicates 16 bit audio */
00144     wsaud->audio_bits = (((header[10] & 0x2) >> 1) + 1) * 8;
00145 
00146     /* initialize the audio decoder stream */
00147     st = av_new_stream(s, 0);
00148     if (!st)
00149         return AVERROR(ENOMEM);
00150     av_set_pts_info(st, 33, 1, wsaud->audio_samplerate);
00151     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00152     st->codec->codec_id = wsaud->audio_type;
00153     st->codec->codec_tag = 0;  /* no tag */
00154     st->codec->channels = wsaud->audio_channels;
00155     st->codec->sample_rate = wsaud->audio_samplerate;
00156     st->codec->bits_per_coded_sample = wsaud->audio_bits;
00157     st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
00158         st->codec->bits_per_coded_sample / 4;
00159     st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;
00160 
00161     wsaud->audio_stream_index = st->index;
00162     wsaud->audio_frame_counter = 0;
00163 
00164     return 0;
00165 }
00166 
00167 static int wsaud_read_packet(AVFormatContext *s,
00168                              AVPacket *pkt)
00169 {
00170     WsAudDemuxContext *wsaud = s->priv_data;
00171     ByteIOContext *pb = s->pb;
00172     unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE];
00173     unsigned int chunk_size;
00174     int ret = 0;
00175 
00176     if (get_buffer(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) !=
00177         AUD_CHUNK_PREAMBLE_SIZE)
00178         return AVERROR(EIO);
00179 
00180     /* validate the chunk */
00181     if (AV_RL32(&preamble[4]) != AUD_CHUNK_SIGNATURE)
00182         return AVERROR_INVALIDDATA;
00183 
00184     chunk_size = AV_RL16(&preamble[0]);
00185     ret= av_get_packet(pb, pkt, chunk_size);
00186     if (ret != chunk_size)
00187         return AVERROR(EIO);
00188     pkt->stream_index = wsaud->audio_stream_index;
00189     pkt->pts = wsaud->audio_frame_counter;
00190     pkt->pts /= wsaud->audio_samplerate;
00191 
00192     /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
00193     wsaud->audio_frame_counter += (chunk_size * 2) / wsaud->audio_channels;
00194 
00195     return ret;
00196 }
00197 
00198 static int wsvqa_probe(AVProbeData *p)
00199 {
00200     /* need 12 bytes to qualify */
00201     if (p->buf_size < 12)
00202         return 0;
00203 
00204     /* check for the VQA signatures */
00205     if ((AV_RB32(&p->buf[0]) != FORM_TAG) ||
00206         (AV_RB32(&p->buf[8]) != WVQA_TAG))
00207         return 0;
00208 
00209     return AVPROBE_SCORE_MAX;
00210 }
00211 
00212 static int wsvqa_read_header(AVFormatContext *s,
00213                              AVFormatParameters *ap)
00214 {
00215     WsVqaDemuxContext *wsvqa = s->priv_data;
00216     ByteIOContext *pb = s->pb;
00217     AVStream *st;
00218     unsigned char *header;
00219     unsigned char scratch[VQA_PREAMBLE_SIZE];
00220     unsigned int chunk_tag;
00221     unsigned int chunk_size;
00222 
00223     /* initialize the video decoder stream */
00224     st = av_new_stream(s, 0);
00225     if (!st)
00226         return AVERROR(ENOMEM);
00227     av_set_pts_info(st, 33, 1, VQA_FRAMERATE);
00228     wsvqa->video_stream_index = st->index;
00229     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00230     st->codec->codec_id = CODEC_ID_WS_VQA;
00231     st->codec->codec_tag = 0;  /* no fourcc */
00232 
00233     /* skip to the start of the VQA header */
00234     url_fseek(pb, 20, SEEK_SET);
00235 
00236     /* the VQA header needs to go to the decoder */
00237     st->codec->extradata_size = VQA_HEADER_SIZE;
00238     st->codec->extradata = av_mallocz(VQA_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
00239     header = (unsigned char *)st->codec->extradata;
00240     if (get_buffer(pb, st->codec->extradata, VQA_HEADER_SIZE) !=
00241         VQA_HEADER_SIZE) {
00242         av_free(st->codec->extradata);
00243         return AVERROR(EIO);
00244     }
00245     st->codec->width = AV_RL16(&header[6]);
00246     st->codec->height = AV_RL16(&header[8]);
00247 
00248     /* initialize the audio decoder stream for VQA v1 or nonzero samplerate */
00249     if (AV_RL16(&header[24]) || (AV_RL16(&header[0]) == 1 && AV_RL16(&header[2]) == 1)) {
00250         st = av_new_stream(s, 0);
00251         if (!st)
00252             return AVERROR(ENOMEM);
00253         av_set_pts_info(st, 33, 1, VQA_FRAMERATE);
00254         st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00255         if (AV_RL16(&header[0]) == 1)
00256             st->codec->codec_id = CODEC_ID_WESTWOOD_SND1;
00257         else
00258             st->codec->codec_id = CODEC_ID_ADPCM_IMA_WS;
00259         st->codec->codec_tag = 0;  /* no tag */
00260         st->codec->sample_rate = AV_RL16(&header[24]);
00261         if (!st->codec->sample_rate)
00262             st->codec->sample_rate = 22050;
00263         st->codec->channels = header[26];
00264         if (!st->codec->channels)
00265             st->codec->channels = 1;
00266         st->codec->bits_per_coded_sample = 16;
00267         st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
00268             st->codec->bits_per_coded_sample / 4;
00269         st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;
00270 
00271         wsvqa->audio_stream_index = st->index;
00272         wsvqa->audio_samplerate = st->codec->sample_rate;
00273         wsvqa->audio_channels = st->codec->channels;
00274         wsvqa->audio_frame_counter = 0;
00275     }
00276 
00277     /* there are 0 or more chunks before the FINF chunk; iterate until
00278      * FINF has been skipped and the file will be ready to be demuxed */
00279     do {
00280         if (get_buffer(pb, scratch, VQA_PREAMBLE_SIZE) != VQA_PREAMBLE_SIZE) {
00281             av_free(st->codec->extradata);
00282             return AVERROR(EIO);
00283         }
00284         chunk_tag = AV_RB32(&scratch[0]);
00285         chunk_size = AV_RB32(&scratch[4]);
00286 
00287         /* catch any unknown header tags, for curiousity */
00288         switch (chunk_tag) {
00289         case CINF_TAG:
00290         case CINH_TAG:
00291         case CIND_TAG:
00292         case PINF_TAG:
00293         case PINH_TAG:
00294         case PIND_TAG:
00295         case FINF_TAG:
00296         case CMDS_TAG:
00297             break;
00298 
00299         default:
00300             av_log (s, AV_LOG_ERROR, " note: unknown chunk seen (%c%c%c%c)\n",
00301                 scratch[0], scratch[1],
00302                 scratch[2], scratch[3]);
00303             break;
00304         }
00305 
00306         url_fseek(pb, chunk_size, SEEK_CUR);
00307     } while (chunk_tag != FINF_TAG);
00308 
00309     return 0;
00310 }
00311 
00312 static int wsvqa_read_packet(AVFormatContext *s,
00313                              AVPacket *pkt)
00314 {
00315     WsVqaDemuxContext *wsvqa = s->priv_data;
00316     ByteIOContext *pb = s->pb;
00317     int ret = -1;
00318     unsigned char preamble[VQA_PREAMBLE_SIZE];
00319     unsigned int chunk_type;
00320     unsigned int chunk_size;
00321     int skip_byte;
00322 
00323     while (get_buffer(pb, preamble, VQA_PREAMBLE_SIZE) == VQA_PREAMBLE_SIZE) {
00324         chunk_type = AV_RB32(&preamble[0]);
00325         chunk_size = AV_RB32(&preamble[4]);
00326         skip_byte = chunk_size & 0x01;
00327 
00328         if ((chunk_type == SND1_TAG) || (chunk_type == SND2_TAG) || (chunk_type == VQFR_TAG)) {
00329 
00330             if (av_new_packet(pkt, chunk_size))
00331                 return AVERROR(EIO);
00332             ret = get_buffer(pb, pkt->data, chunk_size);
00333             if (ret != chunk_size) {
00334                 av_free_packet(pkt);
00335                 return AVERROR(EIO);
00336             }
00337 
00338             if (chunk_type == SND2_TAG) {
00339                 pkt->stream_index = wsvqa->audio_stream_index;
00340                 /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
00341                 wsvqa->audio_frame_counter += (chunk_size * 2) / wsvqa->audio_channels;
00342             } else if(chunk_type == SND1_TAG) {
00343                 pkt->stream_index = wsvqa->audio_stream_index;
00344                 /* unpacked size is stored in header */
00345                 wsvqa->audio_frame_counter += AV_RL16(pkt->data) / wsvqa->audio_channels;
00346             } else {
00347                 pkt->stream_index = wsvqa->video_stream_index;
00348             }
00349             /* stay on 16-bit alignment */
00350             if (skip_byte)
00351                 url_fseek(pb, 1, SEEK_CUR);
00352 
00353             return ret;
00354         } else {
00355             switch(chunk_type){
00356             case CMDS_TAG:
00357             case SND0_TAG:
00358                 break;
00359             default:
00360                 av_log(s, AV_LOG_INFO, "Skipping unknown chunk 0x%08X\n", chunk_type);
00361             }
00362             url_fseek(pb, chunk_size + skip_byte, SEEK_CUR);
00363         }
00364     }
00365 
00366     return ret;
00367 }
00368 
00369 #if CONFIG_WSAUD_DEMUXER
00370 AVInputFormat wsaud_demuxer = {
00371     "wsaud",
00372     NULL_IF_CONFIG_SMALL("Westwood Studios audio format"),
00373     sizeof(WsAudDemuxContext),
00374     wsaud_probe,
00375     wsaud_read_header,
00376     wsaud_read_packet,
00377 };
00378 #endif
00379 #if CONFIG_WSVQA_DEMUXER
00380 AVInputFormat wsvqa_demuxer = {
00381     "wsvqa",
00382     NULL_IF_CONFIG_SMALL("Westwood Studios VQA format"),
00383     sizeof(WsVqaDemuxContext),
00384     wsvqa_probe,
00385     wsvqa_read_header,
00386     wsvqa_read_packet,
00387 };
00388 #endif