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libavformat/adtsenc.c

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00001 /*
00002  * ADTS muxer.
00003  * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
00004  *                    Mans Rullgard <mans@mansr.com>
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * FFmpeg is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with FFmpeg; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include "libavcodec/get_bits.h"
00024 #include "libavcodec/put_bits.h"
00025 #include "libavcodec/avcodec.h"
00026 #include "avformat.h"
00027 #include "adts.h"
00028 
00029 int ff_adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf, int size)
00030 {
00031     GetBitContext gb;
00032     PutBitContext pb;
00033 
00034     init_get_bits(&gb, buf, size * 8);
00035     adts->objecttype = get_bits(&gb, 5) - 1;
00036     adts->sample_rate_index = get_bits(&gb, 4);
00037     adts->channel_conf = get_bits(&gb, 4);
00038 
00039     if (adts->objecttype > 3U) {
00040         av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1);
00041         return -1;
00042     }
00043     if (adts->sample_rate_index == 15) {
00044         av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n");
00045         return -1;
00046     }
00047     if (get_bits(&gb, 1)) {
00048         av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n");
00049         return -1;
00050     }
00051     if (get_bits(&gb, 1)) {
00052         av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n");
00053         return -1;
00054     }
00055     if (get_bits(&gb, 1)) {
00056         av_log_missing_feature(s, "Signaled SBR or PS", 0);
00057         return -1;
00058     }
00059     if (!adts->channel_conf) {
00060         init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE);
00061 
00062         put_bits(&pb, 3, 5); //ID_PCE
00063         adts->pce_size = (ff_copy_pce_data(&pb, &gb) + 3) / 8;
00064         flush_put_bits(&pb);
00065     }
00066 
00067     adts->write_adts = 1;
00068 
00069     return 0;
00070 }
00071 
00072 static int adts_write_header(AVFormatContext *s)
00073 {
00074     ADTSContext *adts = s->priv_data;
00075     AVCodecContext *avc = s->streams[0]->codec;
00076 
00077     if(avc->extradata_size > 0 &&
00078             ff_adts_decode_extradata(s, adts, avc->extradata, avc->extradata_size) < 0)
00079         return -1;
00080 
00081     return 0;
00082 }
00083 
00084 int ff_adts_write_frame_header(ADTSContext *ctx,
00085                                uint8_t *buf, int size, int pce_size)
00086 {
00087     PutBitContext pb;
00088 
00089     init_put_bits(&pb, buf, ADTS_HEADER_SIZE);
00090 
00091     /* adts_fixed_header */
00092     put_bits(&pb, 12, 0xfff);   /* syncword */
00093     put_bits(&pb, 1, 0);        /* ID */
00094     put_bits(&pb, 2, 0);        /* layer */
00095     put_bits(&pb, 1, 1);        /* protection_absent */
00096     put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */
00097     put_bits(&pb, 4, ctx->sample_rate_index);
00098     put_bits(&pb, 1, 0);        /* private_bit */
00099     put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */
00100     put_bits(&pb, 1, 0);        /* original_copy */
00101     put_bits(&pb, 1, 0);        /* home */
00102 
00103     /* adts_variable_header */
00104     put_bits(&pb, 1, 0);        /* copyright_identification_bit */
00105     put_bits(&pb, 1, 0);        /* copyright_identification_start */
00106     put_bits(&pb, 13, ADTS_HEADER_SIZE + size + pce_size); /* aac_frame_length */
00107     put_bits(&pb, 11, 0x7ff);   /* adts_buffer_fullness */
00108     put_bits(&pb, 2, 0);        /* number_of_raw_data_blocks_in_frame */
00109 
00110     flush_put_bits(&pb);
00111 
00112     return 0;
00113 }
00114 
00115 static int adts_write_packet(AVFormatContext *s, AVPacket *pkt)
00116 {
00117     ADTSContext *adts = s->priv_data;
00118     ByteIOContext *pb = s->pb;
00119     uint8_t buf[ADTS_HEADER_SIZE];
00120 
00121     if (!pkt->size)
00122         return 0;
00123     if(adts->write_adts) {
00124         ff_adts_write_frame_header(adts, buf, pkt->size, adts->pce_size);
00125         put_buffer(pb, buf, ADTS_HEADER_SIZE);
00126         if(adts->pce_size) {
00127             put_buffer(pb, adts->pce_data, adts->pce_size);
00128             adts->pce_size = 0;
00129         }
00130     }
00131     put_buffer(pb, pkt->data, pkt->size);
00132     put_flush_packet(pb);
00133 
00134     return 0;
00135 }
00136 
00137 AVOutputFormat adts_muxer = {
00138     "adts",
00139     NULL_IF_CONFIG_SMALL("ADTS AAC"),
00140     "audio/aac",
00141     "aac,adts",
00142     sizeof(ADTSContext),
00143     CODEC_ID_AAC,
00144     CODEC_ID_NONE,
00145     adts_write_header,
00146     adts_write_packet,
00147 };

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