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176 lines
5.5 KiB
176 lines
5.5 KiB
/* |
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* ADTS muxer. |
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* Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com> |
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* Mans Rullgard <mans@mansr.com> |
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* |
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* This file is part of Libav. |
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* |
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* Libav is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* Libav is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with Libav; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "libavcodec/get_bits.h" |
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#include "libavcodec/put_bits.h" |
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#include "libavcodec/avcodec.h" |
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#include "libavcodec/mpeg4audio.h" |
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#include "avformat.h" |
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#define ADTS_HEADER_SIZE 7 |
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typedef struct { |
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int write_adts; |
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int objecttype; |
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int sample_rate_index; |
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int channel_conf; |
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int pce_size; |
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uint8_t pce_data[MAX_PCE_SIZE]; |
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} ADTSContext; |
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#define ADTS_MAX_FRAME_BYTES ((1 << 13) - 1) |
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static int adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf, int size) |
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{ |
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GetBitContext gb; |
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PutBitContext pb; |
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MPEG4AudioConfig m4ac; |
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int off; |
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init_get_bits(&gb, buf, size * 8); |
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off = avpriv_mpeg4audio_get_config(&m4ac, buf, size * 8, 1); |
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if (off < 0) |
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return off; |
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skip_bits_long(&gb, off); |
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adts->objecttype = m4ac.object_type - 1; |
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adts->sample_rate_index = m4ac.sampling_index; |
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adts->channel_conf = m4ac.chan_config; |
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if (adts->objecttype > 3U) { |
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av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1); |
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return -1; |
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} |
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if (adts->sample_rate_index == 15) { |
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av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n"); |
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return -1; |
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} |
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if (get_bits(&gb, 1)) { |
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av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n"); |
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return -1; |
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} |
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if (get_bits(&gb, 1)) { |
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av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n"); |
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return -1; |
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} |
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if (get_bits(&gb, 1)) { |
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av_log(s, AV_LOG_ERROR, "Extension flag is not allowed in ADTS\n"); |
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return -1; |
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} |
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if (!adts->channel_conf) { |
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init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE); |
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put_bits(&pb, 3, 5); //ID_PCE |
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adts->pce_size = (avpriv_copy_pce_data(&pb, &gb) + 3) / 8; |
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flush_put_bits(&pb); |
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} |
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adts->write_adts = 1; |
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return 0; |
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} |
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static int adts_write_header(AVFormatContext *s) |
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{ |
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ADTSContext *adts = s->priv_data; |
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AVCodecContext *avc = s->streams[0]->codec; |
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if (avc->extradata_size > 0 && |
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adts_decode_extradata(s, adts, avc->extradata, avc->extradata_size) < 0) |
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return -1; |
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return 0; |
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} |
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static int adts_write_frame_header(ADTSContext *ctx, |
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uint8_t *buf, int size, int pce_size) |
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{ |
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PutBitContext pb; |
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unsigned full_frame_size = (unsigned)ADTS_HEADER_SIZE + size + pce_size; |
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if (full_frame_size > ADTS_MAX_FRAME_BYTES) { |
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av_log(NULL, AV_LOG_ERROR, "ADTS frame size too large: %u (max %d)\n", |
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full_frame_size, ADTS_MAX_FRAME_BYTES); |
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return AVERROR_INVALIDDATA; |
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} |
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init_put_bits(&pb, buf, ADTS_HEADER_SIZE); |
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/* adts_fixed_header */ |
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put_bits(&pb, 12, 0xfff); /* syncword */ |
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put_bits(&pb, 1, 0); /* ID */ |
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put_bits(&pb, 2, 0); /* layer */ |
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put_bits(&pb, 1, 1); /* protection_absent */ |
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put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */ |
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put_bits(&pb, 4, ctx->sample_rate_index); |
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put_bits(&pb, 1, 0); /* private_bit */ |
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put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */ |
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put_bits(&pb, 1, 0); /* original_copy */ |
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put_bits(&pb, 1, 0); /* home */ |
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/* adts_variable_header */ |
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put_bits(&pb, 1, 0); /* copyright_identification_bit */ |
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put_bits(&pb, 1, 0); /* copyright_identification_start */ |
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put_bits(&pb, 13, full_frame_size); /* aac_frame_length */ |
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put_bits(&pb, 11, 0x7ff); /* adts_buffer_fullness */ |
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put_bits(&pb, 2, 0); /* number_of_raw_data_blocks_in_frame */ |
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flush_put_bits(&pb); |
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return 0; |
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} |
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static int adts_write_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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ADTSContext *adts = s->priv_data; |
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AVIOContext *pb = s->pb; |
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uint8_t buf[ADTS_HEADER_SIZE]; |
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if (!pkt->size) |
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return 0; |
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if (adts->write_adts) { |
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int err = adts_write_frame_header(adts, buf, pkt->size, |
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adts->pce_size); |
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if (err < 0) |
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return err; |
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avio_write(pb, buf, ADTS_HEADER_SIZE); |
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if (adts->pce_size) { |
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avio_write(pb, adts->pce_data, adts->pce_size); |
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adts->pce_size = 0; |
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} |
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} |
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avio_write(pb, pkt->data, pkt->size); |
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return 0; |
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} |
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AVOutputFormat ff_adts_muxer = { |
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.name = "adts", |
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.long_name = NULL_IF_CONFIG_SMALL("ADTS AAC (Advanced Audio Coding)"), |
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.mime_type = "audio/aac", |
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.extensions = "aac,adts", |
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.priv_data_size = sizeof(ADTSContext), |
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.audio_codec = AV_CODEC_ID_AAC, |
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.video_codec = AV_CODEC_ID_NONE, |
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.write_header = adts_write_header, |
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.write_packet = adts_write_packet, |
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.flags = AVFMT_NOTIMESTAMPS, |
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};
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