static int decode_init_mp3on4(AVCodecContext * avctx) { MP3On4DecodeContext *s = avctx->priv_data; int i; if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) { av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n"); return -1; } s->chan_cfg = (((unsigned char *)avctx->extradata)[1] >> 3) & 0x0f; s->frames = mp3Frames[s->chan_cfg]; if(!s->frames) { av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n"); return -1; } avctx->channels = mp3Channels[s->chan_cfg]; /* Init the first mp3 decoder in standard way, so that all tables get builded * We replace avctx->priv_data with the context of the first decoder so that * decode_init() does not have to be changed. * Other decoders will be inited here copying data from the first context */ // Allocate zeroed memory for the first decoder context s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext)); // Put decoder context in place to make init_decode() happy avctx->priv_data = s->mp3decctx[0]; decode_init(avctx); // Restore mp3on4 context pointer avctx->priv_data = s; s->mp3decctx[0]->adu_mode = 1; // Set adu mode /* Create a separate codec/context for each frame (first is already ok). * Each frame is 1 or 2 channels - up to 5 frames allowed */ for (i = 1; i < s->frames; i++) { s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext)); s->mp3decctx[i]->compute_antialias = s->mp3decctx[0]->compute_antialias; s->mp3decctx[i]->adu_mode = 1; s->mp3decctx[i]->avctx = avctx; } return 0; }