| 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 "avcodec.h" |
| 23 | #include "aacadtsdec.h" |
| 24 | #include "put_bits.h" |
| 25 | #include "get_bits.h" |
| 26 | #include "mpeg4audio.h" |
| 27 | #include "internal.h" |
| 28 | |
| 29 | typedef struct AACBSFContext { |
| 30 | int first_frame_done; |
| 31 | } AACBSFContext; |
| 32 | |
| 33 | /** |
| 34 | * This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4 |
| 35 | * ADTS header and removes the ADTS header. |
| 36 | */ |
| 37 | static int aac_adtstoasc_filter(AVBitStreamFilterContext *bsfc, |
| 38 | AVCodecContext *avctx, const char *args, |
| 39 | uint8_t **poutbuf, int *poutbuf_size, |
| 40 | const uint8_t *buf, int buf_size, |
| 41 | int keyframe) |
| 42 | { |
| 43 | GetBitContext gb; |
| 44 | PutBitContext pb; |
| 45 | AACADTSHeaderInfo hdr; |
| 46 | |
| 47 | AACBSFContext *ctx = bsfc->priv_data; |
| 48 | |
| 49 | init_get_bits(&gb, buf, AAC_ADTS_HEADER_SIZE*8); |
| 50 | |
| 51 | *poutbuf = (uint8_t*) buf; |
| 52 | *poutbuf_size = buf_size; |
| 53 | |
| 54 | if (avctx->extradata) |
| 55 | if (show_bits(&gb, 12) != 0xfff) |
| 56 | return 0; |
| 57 | |
| 58 | if (avpriv_aac_parse_header(&gb, &hdr) < 0) { |
| 59 | av_log(avctx, AV_LOG_ERROR, "Error parsing ADTS frame header!\n"); |
| 60 | return AVERROR_INVALIDDATA; |
| 61 | } |
| 62 | |
| 63 | if (!hdr.crc_absent && hdr.num_aac_frames > 1) { |
| 64 | avpriv_report_missing_feature(avctx, |
| 65 | "Multiple RDBs per frame with CRC"); |
| 66 | return AVERROR_PATCHWELCOME; |
| 67 | } |
| 68 | |
| 69 | buf += AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent; |
| 70 | buf_size -= AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent; |
| 71 | |
| 72 | if (!ctx->first_frame_done) { |
| 73 | int pce_size = 0; |
| 74 | uint8_t pce_data[MAX_PCE_SIZE]; |
| 75 | if (!hdr.chan_config) { |
| 76 | init_get_bits(&gb, buf, buf_size * 8); |
| 77 | if (get_bits(&gb, 3) != 5) { |
| 78 | avpriv_report_missing_feature(avctx, |
| 79 | "PCE-based channel configuration " |
| 80 | "without PCE as first syntax " |
| 81 | "element"); |
| 82 | return AVERROR_PATCHWELCOME; |
| 83 | } |
| 84 | init_put_bits(&pb, pce_data, MAX_PCE_SIZE); |
| 85 | pce_size = avpriv_copy_pce_data(&pb, &gb)/8; |
| 86 | flush_put_bits(&pb); |
| 87 | buf_size -= get_bits_count(&gb)/8; |
| 88 | buf += get_bits_count(&gb)/8; |
| 89 | } |
| 90 | av_free(avctx->extradata); |
| 91 | avctx->extradata_size = 2 + pce_size; |
| 92 | avctx->extradata = av_mallocz(avctx->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE); |
| 93 | |
| 94 | init_put_bits(&pb, avctx->extradata, avctx->extradata_size); |
| 95 | put_bits(&pb, 5, hdr.object_type); |
| 96 | put_bits(&pb, 4, hdr.sampling_index); |
| 97 | put_bits(&pb, 4, hdr.chan_config); |
| 98 | put_bits(&pb, 1, 0); //frame length - 1024 samples |
| 99 | put_bits(&pb, 1, 0); //does not depend on core coder |
| 100 | put_bits(&pb, 1, 0); //is not extension |
| 101 | flush_put_bits(&pb); |
| 102 | if (pce_size) { |
| 103 | memcpy(avctx->extradata + 2, pce_data, pce_size); |
| 104 | } |
| 105 | |
| 106 | ctx->first_frame_done = 1; |
| 107 | } |
| 108 | |
| 109 | *poutbuf = (uint8_t*) buf; |
| 110 | *poutbuf_size = buf_size; |
| 111 | |
| 112 | return 0; |
| 113 | } |
| 114 | |
| 115 | AVBitStreamFilter ff_aac_adtstoasc_bsf = { |
| 116 | .name = "aac_adtstoasc", |
| 117 | .priv_data_size = sizeof(AACBSFContext), |
| 118 | .filter = aac_adtstoasc_filter, |
| 119 | }; |