aac_adtstoasc.c (5067B)
1 /* 2 * MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration bitstream filter 3 * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 #include "adts_header.h" 23 #include "adts_parser.h" 24 #include "bsf.h" 25 #include "bsf_internal.h" 26 #include "put_bits.h" 27 #include "get_bits.h" 28 #include "mpeg4audio.h" 29 #include "mpeg4audio_copy_pce.h" 30 31 typedef struct AACBSFContext { 32 int first_frame_done; 33 } AACBSFContext; 34 35 /** 36 * This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4 37 * ADTS header and removes the ADTS header. 38 */ 39 static int aac_adtstoasc_filter(AVBSFContext *bsfc, AVPacket *pkt) 40 { 41 AACBSFContext *ctx = bsfc->priv_data; 42 43 PutBitContext pb; 44 AACADTSHeaderInfo hdr; 45 int ret; 46 47 ret = ff_bsf_get_packet_ref(bsfc, pkt); 48 if (ret < 0) 49 return ret; 50 51 if (bsfc->par_in->extradata && pkt->size >= 2 && (AV_RB16(pkt->data) >> 4) != 0xfff) 52 return 0; 53 54 if (pkt->size < AV_AAC_ADTS_HEADER_SIZE) 55 goto packet_too_small; 56 57 if (ff_adts_header_parse_buf(pkt->data, &hdr) < 0) { 58 av_log(bsfc, AV_LOG_ERROR, "Error parsing ADTS frame header!\n"); 59 ret = AVERROR_INVALIDDATA; 60 goto fail; 61 } 62 63 if (!hdr.crc_absent && hdr.num_aac_frames > 1) { 64 avpriv_report_missing_feature(bsfc, 65 "Multiple RDBs per frame with CRC"); 66 ret = AVERROR_PATCHWELCOME; 67 goto fail; 68 } 69 70 pkt->size -= AV_AAC_ADTS_HEADER_SIZE + 2 * !hdr.crc_absent; 71 if (pkt->size <= 0) 72 goto packet_too_small; 73 pkt->data += AV_AAC_ADTS_HEADER_SIZE + 2 * !hdr.crc_absent; 74 75 if (!ctx->first_frame_done) { 76 int pce_size = 0; 77 uint8_t pce_data[MAX_PCE_SIZE]; 78 uint8_t *extradata; 79 80 if (!hdr.chan_config) { 81 GetBitContext gb; 82 init_get_bits(&gb, pkt->data, pkt->size * 8); 83 if (get_bits(&gb, 3) != 5) { 84 avpriv_report_missing_feature(bsfc, 85 "PCE-based channel configuration " 86 "without PCE as first syntax " 87 "element"); 88 ret = AVERROR_PATCHWELCOME; 89 goto fail; 90 } 91 init_put_bits(&pb, pce_data, MAX_PCE_SIZE); 92 pce_size = ff_copy_pce_data(&pb, &gb) / 8; 93 flush_put_bits(&pb); 94 pkt->size -= get_bits_count(&gb)/8; 95 pkt->data += get_bits_count(&gb)/8; 96 } 97 98 extradata = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, 99 2 + pce_size); 100 if (!extradata) { 101 ret = AVERROR(ENOMEM); 102 goto fail; 103 } 104 105 init_put_bits(&pb, extradata, 2 + pce_size); 106 put_bits(&pb, 5, hdr.object_type); 107 put_bits(&pb, 4, hdr.sampling_index); 108 put_bits(&pb, 4, hdr.chan_config); 109 put_bits(&pb, 1, 0); //frame length - 1024 samples 110 put_bits(&pb, 1, 0); //does not depend on core coder 111 put_bits(&pb, 1, 0); //is not extension 112 flush_put_bits(&pb); 113 if (pce_size) { 114 memcpy(extradata + 2, pce_data, pce_size); 115 } 116 117 ctx->first_frame_done = 1; 118 } 119 120 return 0; 121 122 packet_too_small: 123 av_log(bsfc, AV_LOG_ERROR, "Input packet too small\n"); 124 ret = AVERROR_INVALIDDATA; 125 fail: 126 av_packet_unref(pkt); 127 return ret; 128 } 129 130 static int aac_adtstoasc_init(AVBSFContext *ctx) 131 { 132 /* Validate the extradata if the stream is already MPEG-4 AudioSpecificConfig */ 133 if (ctx->par_in->extradata) { 134 MPEG4AudioConfig mp4ac; 135 int ret = avpriv_mpeg4audio_get_config2(&mp4ac, ctx->par_in->extradata, 136 ctx->par_in->extradata_size, 1, ctx); 137 if (ret < 0) { 138 av_log(ctx, AV_LOG_ERROR, "Error parsing AudioSpecificConfig extradata!\n"); 139 return ret; 140 } 141 } 142 143 return 0; 144 } 145 146 static const enum AVCodecID codec_ids[] = { 147 AV_CODEC_ID_AAC, AV_CODEC_ID_NONE, 148 }; 149 150 const FFBitStreamFilter ff_aac_adtstoasc_bsf = { 151 .p.name = "aac_adtstoasc", 152 .p.codec_ids = codec_ids, 153 .priv_data_size = sizeof(AACBSFContext), 154 .init = aac_adtstoasc_init, 155 .filter = aac_adtstoasc_filter, 156 };