/* * MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration bitstream filter * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "adts_header.h" #include "adts_parser.h" #include "avcodec.h" #include "bsf.h" #include "put_bits.h" #include "get_bits.h" #include "mpeg4audio.h" #include "internal.h" typedef struct AACBSFContext { int first_frame_done; } AACBSFContext; /** * This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4 * ADTS header and removes the ADTS header. */ static int aac_adtstoasc_filter(AVBSFContext *bsfc, AVPacket *pkt) { AACBSFContext *ctx = bsfc->priv_data; GetBitContext gb; PutBitContext pb; AACADTSHeaderInfo hdr; int ret; ret = ff_bsf_get_packet_ref(bsfc, pkt); if (ret < 0) return ret; if (bsfc->par_in->extradata && pkt->size >= 2 && (AV_RB16(pkt->data) >> 4) != 0xfff) return 0; if (pkt->size < AV_AAC_ADTS_HEADER_SIZE) goto packet_too_small; init_get_bits(&gb, pkt->data, AV_AAC_ADTS_HEADER_SIZE * 8); if (ff_adts_header_parse(&gb, &hdr) < 0) { av_log(bsfc, AV_LOG_ERROR, "Error parsing ADTS frame header!\n"); ret = AVERROR_INVALIDDATA; goto fail; } if (!hdr.crc_absent && hdr.num_aac_frames > 1) { avpriv_report_missing_feature(bsfc, "Multiple RDBs per frame with CRC"); ret = AVERROR_PATCHWELCOME; goto fail; } pkt->size -= AV_AAC_ADTS_HEADER_SIZE + 2 * !hdr.crc_absent; if (pkt->size <= 0) goto packet_too_small; pkt->data += AV_AAC_ADTS_HEADER_SIZE + 2 * !hdr.crc_absent; if (!ctx->first_frame_done) { int pce_size = 0; uint8_t pce_data[MAX_PCE_SIZE]; uint8_t *extradata; if (!hdr.chan_config) { init_get_bits(&gb, pkt->data, pkt->size * 8); if (get_bits(&gb, 3) != 5) { avpriv_report_missing_feature(bsfc, "PCE-based channel configuration " "without PCE as first syntax " "element"); ret = AVERROR_PATCHWELCOME; goto fail; } init_put_bits(&pb, pce_data, MAX_PCE_SIZE); pce_size = ff_copy_pce_data(&pb, &gb) / 8; flush_put_bits(&pb); pkt->size -= get_bits_count(&gb)/8; pkt->data += get_bits_count(&gb)/8; } extradata = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, 2 + pce_size); if (!extradata) { ret = AVERROR(ENOMEM); goto fail; } init_put_bits(&pb, extradata, 2 + pce_size); put_bits(&pb, 5, hdr.object_type); put_bits(&pb, 4, hdr.sampling_index); put_bits(&pb, 4, hdr.chan_config); put_bits(&pb, 1, 0); //frame length - 1024 samples put_bits(&pb, 1, 0); //does not depend on core coder put_bits(&pb, 1, 0); //is not extension flush_put_bits(&pb); if (pce_size) { memcpy(extradata + 2, pce_data, pce_size); } ctx->first_frame_done = 1; } return 0; packet_too_small: av_log(bsfc, AV_LOG_ERROR, "Input packet too small\n"); ret = AVERROR_INVALIDDATA; fail: av_packet_unref(pkt); return ret; } static int aac_adtstoasc_init(AVBSFContext *ctx) { /* Validate the extradata if the stream is already MPEG-4 AudioSpecificConfig */ if (ctx->par_in->extradata) { MPEG4AudioConfig mp4ac; int ret = avpriv_mpeg4audio_get_config2(&mp4ac, ctx->par_in->extradata, ctx->par_in->extradata_size, 1, ctx); if (ret < 0) { av_log(ctx, AV_LOG_ERROR, "Error parsing AudioSpecificConfig extradata!\n"); return ret; } } return 0; } static const enum AVCodecID codec_ids[] = { AV_CODEC_ID_AAC, AV_CODEC_ID_NONE, }; const AVBitStreamFilter ff_aac_adtstoasc_bsf = { .name = "aac_adtstoasc", .priv_data_size = sizeof(AACBSFContext), .init = aac_adtstoasc_init, .filter = aac_adtstoasc_filter, .codec_ids = codec_ids, };