static int ogg_read_header(AVFormatContext *avfcontext, AVFormatParameters *ap) { OggContext *context = avfcontext->priv_data; ogg_packet op ; char *buf ; ogg_page og ; AVStream *ast ; AVCodecContext *codec; uint8_t *p; int i; ogg_sync_init(&context->oy) ; buf = ogg_sync_buffer(&context->oy, DECODER_BUFFER_SIZE) ; if(get_buffer(&avfcontext->pb, buf, DECODER_BUFFER_SIZE) <= 0) return AVERROR_IO ; ogg_sync_wrote(&context->oy, DECODER_BUFFER_SIZE) ; ogg_sync_pageout(&context->oy, &og) ; ogg_stream_init(&context->os, ogg_page_serialno(&og)) ; ogg_stream_pagein(&context->os, &og) ; /* currently only one vorbis stream supported */ ast = av_new_stream(avfcontext, 0) ; if(!ast) return AVERROR_NOMEM ; av_set_pts_info(ast, 60, 1, AV_TIME_BASE); codec= &ast->codec; codec->codec_type = CODEC_TYPE_AUDIO; codec->codec_id = CODEC_ID_VORBIS; for(i=0; i<3; i++){ if(next_packet(avfcontext, &op)){ } codec->extradata_size+= 2 + op.bytes; codec->extradata= av_realloc(codec->extradata, codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE); p= codec->extradata + codec->extradata_size - 2 - op.bytes; *(p++)= op.bytes>>8; *(p++)= op.bytes&0xFF; memcpy(p, op.packet, op.bytes); } return 0 ; }