MythTV: sierravmd.c Source File

00001 /*
00002  * Sierra VMD Format Demuxer
00003  * Copyright (c) 2004 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 
00030 #include "avformat.h"
00031 
00032 #define VMD_HEADER_SIZE 0x0330
00033 #define BYTES_PER_FRAME_RECORD 16
00034 
00035 typedef struct {
00036   int stream_index;
00037   offset_t frame_offset;
00038   unsigned int frame_size;
00039   int64_t pts;
00040   int keyframe;
00041   unsigned char frame_record[BYTES_PER_FRAME_RECORD];
00042 } vmd_frame_t;
00043 
00044 typedef struct VmdDemuxContext {
00045     int video_stream_index;
00046     int audio_stream_index;
00047 
00048     unsigned int frame_count;
00049     unsigned int frames_per_block;
00050     vmd_frame_t *frame_table;
00051     unsigned int current_frame;
00052 
00053     int sample_rate;
00054     int64_t audio_sample_counter;
00055     int skiphdr;
00056 
00057     unsigned char vmd_header[VMD_HEADER_SIZE];
00058 } VmdDemuxContext;
00059 
00060 static int vmd_probe(AVProbeData *p)
00061 {
00062     /* check if the first 2 bytes of the file contain the appropriate size
00063      * of a VMD header chunk */
00064     if (AV_RL16(&p->buf[0]) != VMD_HEADER_SIZE - 2)
00065         return 0;
00066 
00067     /* only return half certainty since this check is a bit sketchy */
00068     return AVPROBE_SCORE_MAX / 2;
00069 }
00070 
00071 static int vmd_read_header(AVFormatContext *s,
00072                            AVFormatParameters *ap)
00073 {
00074     VmdDemuxContext *vmd = s->priv_data;
00075     ByteIOContext *pb = &s->pb;
00076     AVStream *st, *vst;
00077     unsigned int toc_offset;
00078     unsigned char *raw_frame_table;
00079     int raw_frame_table_size;
00080     offset_t current_offset;
00081     int i, j;
00082     unsigned int total_frames;
00083     int64_t pts_inc = 1;
00084     int64_t current_video_pts = 0, current_audio_pts = 0;
00085     unsigned char chunk[BYTES_PER_FRAME_RECORD];
00086     int num, den;
00087     int sound_buffers;
00088 
00089     /* fetch the main header, including the 2 header length bytes */
00090     url_fseek(pb, 0, SEEK_SET);
00091     if (get_buffer(pb, vmd->vmd_header, VMD_HEADER_SIZE) != VMD_HEADER_SIZE)
00092         return AVERROR(EIO);
00093 
00094     /* start up the decoders */
00095     vst = av_new_stream(s, 0);
00096     if (!vst)
00097         return AVERROR(ENOMEM);
00098     av_set_pts_info(vst, 33, 1, 10);
00099     vmd->video_stream_index = vst->index;
00100     vst->codec->codec_type = CODEC_TYPE_VIDEO;
00101     vst->codec->codec_id = CODEC_ID_VMDVIDEO;
00102     vst->codec->codec_tag = 0;  /* no fourcc */
00103     vst->codec->width = AV_RL16(&vmd->vmd_header[12]);
00104     vst->codec->height = AV_RL16(&vmd->vmd_header[14]);
00105     vst->codec->extradata_size = VMD_HEADER_SIZE;
00106     vst->codec->extradata = av_mallocz(VMD_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
00107     memcpy(vst->codec->extradata, vmd->vmd_header, VMD_HEADER_SIZE);
00108 
00109     /* if sample rate is 0, assume no audio */
00110     vmd->sample_rate = AV_RL16(&vmd->vmd_header[804]);
00111     if (vmd->sample_rate) {
00112         st = av_new_stream(s, 0);
00113         if (!st)
00114             return AVERROR(ENOMEM);
00115         vmd->audio_stream_index = st->index;
00116         st->codec->codec_type = CODEC_TYPE_AUDIO;
00117         st->codec->codec_id = CODEC_ID_VMDAUDIO;
00118         st->codec->codec_tag = 0;  /* no fourcc */
00119         st->codec->channels = (vmd->vmd_header[811] & 0x80) ? 2 : 1;
00120         st->codec->sample_rate = vmd->sample_rate;
00121         st->codec->block_align = AV_RL16(&vmd->vmd_header[806]);
00122         if (st->codec->block_align & 0x8000) {
00123             st->codec->bits_per_sample = 16;
00124             st->codec->block_align = -(st->codec->block_align - 0x10000);
00125         } else {
00126             st->codec->bits_per_sample = 8;
00127         }
00128         st->codec->bit_rate = st->codec->sample_rate *
00129             st->codec->bits_per_sample * st->codec->channels;
00130 
00131         /* calculate pts */
00132         num = st->codec->block_align;
00133         den = st->codec->sample_rate * st->codec->channels;
00134         av_reduce(&den, &num, den, num, (1UL<<31)-1);
00135         av_set_pts_info(vst, 33, num, den);
00136         av_set_pts_info(st, 33, num, den);
00137         pts_inc = num;
00138     }
00139 
00140     toc_offset = AV_RL32(&vmd->vmd_header[812]);
00141     vmd->frame_count = AV_RL16(&vmd->vmd_header[6]);
00142     vmd->frames_per_block = AV_RL16(&vmd->vmd_header[18]);
00143     url_fseek(pb, toc_offset, SEEK_SET);
00144 
00145     raw_frame_table = NULL;
00146     vmd->frame_table = NULL;
00147     sound_buffers = AV_RL16(&vmd->vmd_header[808]);
00148     raw_frame_table_size = vmd->frame_count * 6;
00149     raw_frame_table = av_malloc(raw_frame_table_size);
00150     if(vmd->frame_count * vmd->frames_per_block  >= UINT_MAX / sizeof(vmd_frame_t)){
00151         av_log(s, AV_LOG_ERROR, "vmd->frame_count * vmd->frames_per_block too large\n");
00152         return -1;
00153     }
00154     vmd->frame_table = av_malloc((vmd->frame_count * vmd->frames_per_block + sound_buffers) * sizeof(vmd_frame_t));
00155     if (!raw_frame_table || !vmd->frame_table) {
00156         av_free(raw_frame_table);
00157         av_free(vmd->frame_table);
00158         return AVERROR(ENOMEM);
00159     }
00160     if (get_buffer(pb, raw_frame_table, raw_frame_table_size) !=
00161         raw_frame_table_size) {
00162         av_free(raw_frame_table);
00163         av_free(vmd->frame_table);
00164         return AVERROR(EIO);
00165     }
00166 
00167     total_frames = 0;
00168     for (i = 0; i < vmd->frame_count; i++) {
00169 
00170         current_offset = AV_RL32(&raw_frame_table[6 * i + 2]);
00171 
00172         /* handle each entry in index block */
00173         for (j = 0; j < vmd->frames_per_block; j++) {
00174             int type;
00175             uint32_t size;
00176 
00177             get_buffer(pb, chunk, BYTES_PER_FRAME_RECORD);
00178             type = chunk[0];
00179             size = AV_RL32(&chunk[2]);
00180             if(!size)
00181                 continue;
00182             switch(type) {
00183             case 1: /* Audio Chunk */
00184                 /* first audio chunk contains several audio buffers */
00185                 if(current_audio_pts){
00186                     vmd->frame_table[total_frames].frame_offset = current_offset;
00187                     vmd->frame_table[total_frames].stream_index = vmd->audio_stream_index;
00188                     vmd->frame_table[total_frames].frame_size = size;
00189                     memcpy(vmd->frame_table[total_frames].frame_record, chunk, BYTES_PER_FRAME_RECORD);
00190                     vmd->frame_table[total_frames].pts = current_audio_pts;
00191                     total_frames++;
00192                     current_audio_pts += pts_inc;
00193                 }else{
00194                     uint32_t flags;
00195                     int k;
00196                     int noff;
00197                     int64_t pos;
00198 
00199                     pos = url_ftell(pb);
00200                     url_fseek(pb, current_offset, SEEK_SET);
00201                     flags = get_le32(pb);
00202                     noff = 4;
00203                     url_fseek(pb, pos, SEEK_SET);
00204                     av_log(s, AV_LOG_DEBUG, "Sound mapping = %08X (%i bufs)\n", flags, sound_buffers);
00205                     for(k = 0; k < sound_buffers - 1; k++){
00206                         if(flags & 1) { /* silent block */
00207                             vmd->frame_table[total_frames].frame_size = 0;
00208                         }else{
00209                             vmd->frame_table[total_frames].frame_size = st->codec->block_align + (st->codec->block_align & 1);
00210                         }
00211                         noff += vmd->frame_table[total_frames].frame_size;
00212                         vmd->frame_table[total_frames].frame_offset = current_offset + noff;
00213                         vmd->frame_table[total_frames].stream_index = vmd->audio_stream_index;
00214                         memcpy(vmd->frame_table[total_frames].frame_record, chunk, BYTES_PER_FRAME_RECORD);
00215                         vmd->frame_table[total_frames].pts = current_audio_pts;
00216                         total_frames++;
00217                         current_audio_pts += pts_inc;
00218                         flags >>= 1;
00219                     }
00220                 }
00221                 break;
00222             case 2: /* Video Chunk */
00223                 vmd->frame_table[total_frames].frame_offset = current_offset;
00224                 vmd->frame_table[total_frames].stream_index = vmd->video_stream_index;
00225                 vmd->frame_table[total_frames].frame_size = size;
00226                 memcpy(vmd->frame_table[total_frames].frame_record, chunk, BYTES_PER_FRAME_RECORD);
00227                 vmd->frame_table[total_frames].pts = current_video_pts;
00228                 total_frames++;
00229                 break;
00230             }
00231             current_offset += size;
00232         }
00233         current_video_pts += pts_inc;
00234     }
00235 
00236     av_free(raw_frame_table);
00237 
00238     vmd->current_frame = 0;
00239     vmd->frame_count = total_frames;
00240 
00241     return 0;
00242 }
00243 
00244 static int vmd_read_packet(AVFormatContext *s,
00245                            AVPacket *pkt)
00246 {
00247     VmdDemuxContext *vmd = s->priv_data;
00248     ByteIOContext *pb = &s->pb;
00249     int ret = 0;
00250     vmd_frame_t *frame;
00251 
00252     if (vmd->current_frame >= vmd->frame_count)
00253         return AVERROR(EIO);
00254 
00255     frame = &vmd->frame_table[vmd->current_frame];
00256     /* position the stream (will probably be there already) */
00257     url_fseek(pb, frame->frame_offset, SEEK_SET);
00258 
00259     if (av_new_packet(pkt, frame->frame_size + BYTES_PER_FRAME_RECORD))
00260         return AVERROR(ENOMEM);
00261     pkt->pos= url_ftell(pb);
00262     memcpy(pkt->data, frame->frame_record, BYTES_PER_FRAME_RECORD);
00263     ret = get_buffer(pb, pkt->data + BYTES_PER_FRAME_RECORD,
00264         frame->frame_size);
00265 
00266     if (ret != frame->frame_size) {
00267         av_free_packet(pkt);
00268         ret = AVERROR(EIO);
00269     }
00270     pkt->stream_index = frame->stream_index;
00271     pkt->pts = frame->pts;
00272     av_log(NULL, AV_LOG_DEBUG, " dispatching %s frame with %d bytes and pts %"PRId64"\n",
00273             (frame->frame_record[0] == 0x02) ? "video" : "audio",
00274             frame->frame_size + BYTES_PER_FRAME_RECORD,
00275             pkt->pts);
00276 
00277     vmd->current_frame++;
00278 
00279     return ret;
00280 }
00281 
00282 static int vmd_read_close(AVFormatContext *s)
00283 {
00284     VmdDemuxContext *vmd = s->priv_data;
00285 
00286     av_free(vmd->frame_table);
00287 
00288     return 0;
00289 }
00290 
00291 AVInputFormat vmd_demuxer = {
00292     "vmd",
00293     "Sierra VMD format",
00294     sizeof(VmdDemuxContext),
00295     vmd_probe,
00296     vmd_read_header,
00297     vmd_read_packet,
00298     vmd_read_close,
00299 };