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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 | }; |