| 1 | /* |
| 2 | * LATM/LOAS muxer |
| 3 | * Copyright (c) 2011 Kieran Kunhya <kieran@kunhya.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 "libavcodec/get_bits.h" |
| 23 | #include "libavcodec/put_bits.h" |
| 24 | #include "libavcodec/avcodec.h" |
| 25 | #include "libavcodec/mpeg4audio.h" |
| 26 | #include "libavutil/opt.h" |
| 27 | #include "avformat.h" |
| 28 | #include "rawenc.h" |
| 29 | |
| 30 | #define MAX_EXTRADATA_SIZE 1024 |
| 31 | |
| 32 | typedef struct { |
| 33 | AVClass *av_class; |
| 34 | int off; |
| 35 | int channel_conf; |
| 36 | int object_type; |
| 37 | int counter; |
| 38 | int mod; |
| 39 | uint8_t buffer[0x1fff + MAX_EXTRADATA_SIZE + 1024]; |
| 40 | } LATMContext; |
| 41 | |
| 42 | static const AVOption options[] = { |
| 43 | {"smc-interval", "StreamMuxConfig interval.", |
| 44 | offsetof(LATMContext, mod), AV_OPT_TYPE_INT, {.i64 = 0x0014}, 0x0001, 0xffff, AV_OPT_FLAG_ENCODING_PARAM}, |
| 45 | {NULL}, |
| 46 | }; |
| 47 | |
| 48 | static const AVClass latm_muxer_class = { |
| 49 | .class_name = "LATM/LOAS muxer", |
| 50 | .item_name = av_default_item_name, |
| 51 | .option = options, |
| 52 | .version = LIBAVUTIL_VERSION_INT, |
| 53 | }; |
| 54 | |
| 55 | static int latm_decode_extradata(LATMContext *ctx, uint8_t *buf, int size) |
| 56 | { |
| 57 | MPEG4AudioConfig m4ac; |
| 58 | |
| 59 | if (size > MAX_EXTRADATA_SIZE) { |
| 60 | av_log(ctx, AV_LOG_ERROR, "Extradata is larger than currently supported.\n"); |
| 61 | return AVERROR_INVALIDDATA; |
| 62 | } |
| 63 | ctx->off = avpriv_mpeg4audio_get_config(&m4ac, buf, size * 8, 1); |
| 64 | if (ctx->off < 0) |
| 65 | return ctx->off; |
| 66 | |
| 67 | if (ctx->object_type == AOT_ALS && (ctx->off & 7)) { |
| 68 | // as long as avpriv_mpeg4audio_get_config works correctly this is impossible |
| 69 | av_log(ctx, AV_LOG_ERROR, "BUG: ALS offset is not byte-aligned\n"); |
| 70 | return AVERROR_INVALIDDATA; |
| 71 | } |
| 72 | /* FIXME: are any formats not allowed in LATM? */ |
| 73 | |
| 74 | if (m4ac.object_type > AOT_SBR && m4ac.object_type != AOT_ALS) { |
| 75 | av_log(ctx, AV_LOG_ERROR, "Muxing MPEG-4 AOT %d in LATM is not supported\n", m4ac.object_type); |
| 76 | return AVERROR_INVALIDDATA; |
| 77 | } |
| 78 | ctx->channel_conf = m4ac.chan_config; |
| 79 | ctx->object_type = m4ac.object_type; |
| 80 | |
| 81 | return 0; |
| 82 | } |
| 83 | |
| 84 | static int latm_write_header(AVFormatContext *s) |
| 85 | { |
| 86 | LATMContext *ctx = s->priv_data; |
| 87 | AVCodecContext *avctx = s->streams[0]->codec; |
| 88 | |
| 89 | if (avctx->codec_id == AV_CODEC_ID_AAC_LATM) |
| 90 | return 0; |
| 91 | |
| 92 | if (avctx->extradata_size > 0 && |
| 93 | latm_decode_extradata(ctx, avctx->extradata, avctx->extradata_size) < 0) |
| 94 | return AVERROR_INVALIDDATA; |
| 95 | |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | static void latm_write_frame_header(AVFormatContext *s, PutBitContext *bs) |
| 100 | { |
| 101 | LATMContext *ctx = s->priv_data; |
| 102 | AVCodecContext *avctx = s->streams[0]->codec; |
| 103 | int header_size; |
| 104 | |
| 105 | /* AudioMuxElement */ |
| 106 | put_bits(bs, 1, !!ctx->counter); |
| 107 | |
| 108 | if (!ctx->counter) { |
| 109 | /* StreamMuxConfig */ |
| 110 | put_bits(bs, 1, 0); /* audioMuxVersion */ |
| 111 | put_bits(bs, 1, 1); /* allStreamsSameTimeFraming */ |
| 112 | put_bits(bs, 6, 0); /* numSubFrames */ |
| 113 | put_bits(bs, 4, 0); /* numProgram */ |
| 114 | put_bits(bs, 3, 0); /* numLayer */ |
| 115 | |
| 116 | /* AudioSpecificConfig */ |
| 117 | if (ctx->object_type == AOT_ALS) { |
| 118 | header_size = avctx->extradata_size-(ctx->off >> 3); |
| 119 | avpriv_copy_bits(bs, &avctx->extradata[ctx->off >> 3], header_size); |
| 120 | } else { |
| 121 | // + 3 assumes not scalable and dependsOnCoreCoder == 0, |
| 122 | // see decode_ga_specific_config in libavcodec/aacdec.c |
| 123 | avpriv_copy_bits(bs, avctx->extradata, ctx->off + 3); |
| 124 | |
| 125 | if (!ctx->channel_conf) { |
| 126 | GetBitContext gb; |
| 127 | init_get_bits8(&gb, avctx->extradata, avctx->extradata_size); |
| 128 | skip_bits_long(&gb, ctx->off + 3); |
| 129 | avpriv_copy_pce_data(bs, &gb); |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | put_bits(bs, 3, 0); /* frameLengthType */ |
| 134 | put_bits(bs, 8, 0xff); /* latmBufferFullness */ |
| 135 | |
| 136 | put_bits(bs, 1, 0); /* otherDataPresent */ |
| 137 | put_bits(bs, 1, 0); /* crcCheckPresent */ |
| 138 | } |
| 139 | |
| 140 | ctx->counter++; |
| 141 | ctx->counter %= ctx->mod; |
| 142 | } |
| 143 | |
| 144 | static int latm_write_packet(AVFormatContext *s, AVPacket *pkt) |
| 145 | { |
| 146 | LATMContext *ctx = s->priv_data; |
| 147 | AVIOContext *pb = s->pb; |
| 148 | PutBitContext bs; |
| 149 | int i, len; |
| 150 | uint8_t loas_header[] = "\x56\xe0\x00"; |
| 151 | |
| 152 | if (s->streams[0]->codec->codec_id == AV_CODEC_ID_AAC_LATM) |
| 153 | return ff_raw_write_packet(s, pkt); |
| 154 | |
| 155 | if (pkt->size > 2 && pkt->data[0] == 0xff && (pkt->data[1] >> 4) == 0xf) { |
| 156 | av_log(s, AV_LOG_ERROR, "ADTS header detected - ADTS will not be incorrectly muxed into LATM\n"); |
| 157 | return AVERROR_INVALIDDATA; |
| 158 | } |
| 159 | |
| 160 | if (!s->streams[0]->codec->extradata) { |
| 161 | if(pkt->size > 2 && pkt->data[0] == 0x56 && (pkt->data[1] >> 4) == 0xe && |
| 162 | (AV_RB16(pkt->data + 1) & 0x1FFF) + 3 == pkt->size) |
| 163 | return ff_raw_write_packet(s, pkt); |
| 164 | else |
| 165 | return AVERROR_INVALIDDATA; |
| 166 | } |
| 167 | |
| 168 | if (pkt->size > 0x1fff) |
| 169 | goto too_large; |
| 170 | |
| 171 | init_put_bits(&bs, ctx->buffer, pkt->size+1024+MAX_EXTRADATA_SIZE); |
| 172 | |
| 173 | latm_write_frame_header(s, &bs); |
| 174 | |
| 175 | /* PayloadLengthInfo() */ |
| 176 | for (i = 0; i <= pkt->size-255; i+=255) |
| 177 | put_bits(&bs, 8, 255); |
| 178 | |
| 179 | put_bits(&bs, 8, pkt->size-i); |
| 180 | |
| 181 | /* The LATM payload is written unaligned */ |
| 182 | |
| 183 | /* PayloadMux() */ |
| 184 | if (pkt->size && (pkt->data[0] & 0xe1) == 0x81) { |
| 185 | // Convert byte-aligned DSE to non-aligned. |
| 186 | // Due to the input format encoding we know that |
| 187 | // it is naturally byte-aligned in the input stream, |
| 188 | // so there are no padding bits to account for. |
| 189 | // To avoid having to add padding bits and rearrange |
| 190 | // the whole stream we just remove the byte-align flag. |
| 191 | // This allows us to remux our FATE AAC samples into latm |
| 192 | // files that are still playable with minimal effort. |
| 193 | put_bits(&bs, 8, pkt->data[0] & 0xfe); |
| 194 | avpriv_copy_bits(&bs, pkt->data + 1, 8*pkt->size - 8); |
| 195 | } else |
| 196 | avpriv_copy_bits(&bs, pkt->data, 8*pkt->size); |
| 197 | |
| 198 | avpriv_align_put_bits(&bs); |
| 199 | flush_put_bits(&bs); |
| 200 | |
| 201 | len = put_bits_count(&bs) >> 3; |
| 202 | |
| 203 | if (len > 0x1fff) |
| 204 | goto too_large; |
| 205 | |
| 206 | loas_header[1] |= (len >> 8) & 0x1f; |
| 207 | loas_header[2] |= len & 0xff; |
| 208 | |
| 209 | avio_write(pb, loas_header, 3); |
| 210 | avio_write(pb, ctx->buffer, len); |
| 211 | |
| 212 | return 0; |
| 213 | |
| 214 | too_large: |
| 215 | av_log(s, AV_LOG_ERROR, "LATM packet size larger than maximum size 0x1fff\n"); |
| 216 | return AVERROR_INVALIDDATA; |
| 217 | } |
| 218 | |
| 219 | AVOutputFormat ff_latm_muxer = { |
| 220 | .name = "latm", |
| 221 | .long_name = NULL_IF_CONFIG_SMALL("LOAS/LATM"), |
| 222 | .mime_type = "audio/MP4A-LATM", |
| 223 | .extensions = "latm,loas", |
| 224 | .priv_data_size = sizeof(LATMContext), |
| 225 | .audio_codec = AV_CODEC_ID_AAC, |
| 226 | .video_codec = AV_CODEC_ID_NONE, |
| 227 | .write_header = latm_write_header, |
| 228 | .write_packet = latm_write_packet, |
| 229 | .priv_class = &latm_muxer_class, |
| 230 | .flags = AVFMT_NOTIMESTAMPS, |
| 231 | }; |