static int oggvorbis_decode_init(AVCodecContext *avccontext) { OggVorbisDecContext *context = avccontext->priv_data ; uint8_t *p= avccontext->extradata; int i, hsizes[3]; unsigned char *headers[3], *extradata = avccontext->extradata; vorbis_info_init(&context->vi) ; vorbis_comment_init(&context->vc) ; if(! avccontext->extradata_size || ! p) { av_log(avccontext, AV_LOG_ERROR, "vorbis extradata absent\n"); return -1; } if(p[0] == 0 && p[1] == 30) { for(i = 0; i < 3; i++){ hsizes[i] = bytestream_get_be16((const uint8_t **)&p); headers[i] = p; p += hsizes[i]; } } else if(*p == 2) { unsigned int offset = 1; p++; for(i=0; i<2; i++) { hsizes[i] = 0; while((*p == 0xFF) && (offset < avccontext->extradata_size)) { hsizes[i] += 0xFF; offset++; p++; } if(offset >= avccontext->extradata_size - 1) { av_log(avccontext, AV_LOG_ERROR, "vorbis header sizes damaged\n"); return -1; } hsizes[i] += *p; offset++; p++; } hsizes[2] = avccontext->extradata_size - hsizes[0]-hsizes[1]-offset; #if 0 av_log(avccontext, AV_LOG_DEBUG, "vorbis header sizes: %d, %d, %d, / extradata_len is %d \n", hsizes[0], hsizes[1], hsizes[2], avccontext->extradata_size); #endif headers[0] = extradata + offset; headers[1] = extradata + offset + hsizes[0]; headers[2] = extradata + offset + hsizes[0] + hsizes[1]; } else { av_log(avccontext, AV_LOG_ERROR, "vorbis initial header len is wrong: %d\n", *p); return -1; } for(i=0; i<3; i++){ context->op.b_o_s= i==0; context->op.bytes = hsizes[i]; context->op.packet = headers[i]; if(vorbis_synthesis_headerin(&context->vi, &context->vc, &context->op)<0){ av_log(avccontext, AV_LOG_ERROR, "%d. vorbis header damaged\n", i+1); return -1; } } avccontext->channels = context->vi.channels; avccontext->sample_rate = context->vi.rate; avccontext->sample_fmt = AV_SAMPLE_FMT_S16; avccontext->time_base= (AVRational){1, avccontext->sample_rate}; vorbis_synthesis_init(&context->vd, &context->vi); vorbis_block_init(&context->vd, &context->vb); return 0 ; }