path: root/libavcodec/aac_adtstoasc_bsf.c (plain)
blob: 1067160559c9d5df5ea0a966dd6f1ab9aa8ecf5e

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 "bsf.h"
25	#include "put_bits.h"
26	#include "get_bits.h"
27	#include "mpeg4audio.h"
28	#include "internal.h"
29
30	typedef struct AACBSFContext {
31	int first_frame_done;
32	} AACBSFContext;
33
34	/**
35	* This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4
36	* ADTS header and removes the ADTS header.
37	*/
38	static int aac_adtstoasc_filter(AVBSFContext *bsfc, AVPacket *out)
39	{
40	AACBSFContext *ctx = bsfc->priv_data;
41
42	GetBitContext gb;
43	PutBitContext pb;
44	AACADTSHeaderInfo hdr;
45	AVPacket *in;
46	int ret;
47
48	ret = ff_bsf_get_packet(bsfc, &in);
49	if (ret < 0)
50	return ret;
51
52	if (in->size < AAC_ADTS_HEADER_SIZE)
53	goto packet_too_small;
54
55	init_get_bits(&gb, in->data, AAC_ADTS_HEADER_SIZE * 8);
56
57	if (bsfc->par_in->extradata && show_bits(&gb, 12) != 0xfff)
58	goto finish;
59
60	if (avpriv_aac_parse_header(&gb, &hdr) < 0) {
61	av_log(bsfc, AV_LOG_ERROR, "Error parsing ADTS frame header!\n");
62	ret = AVERROR_INVALIDDATA;
63	goto fail;
64	}
65
66	if (!hdr.crc_absent && hdr.num_aac_frames > 1) {
67	avpriv_report_missing_feature(bsfc,
68	"Multiple RDBs per frame with CRC");
69	ret = AVERROR_PATCHWELCOME;
70	goto fail;
71	}
72
73	in->size -= AAC_ADTS_HEADER_SIZE + 2 * !hdr.crc_absent;
74	if (in->size <= 0)
75	goto packet_too_small;
76	in->data += AAC_ADTS_HEADER_SIZE + 2 * !hdr.crc_absent;
77
78	if (!ctx->first_frame_done) {
79	int pce_size = 0;
80	uint8_t pce_data[MAX_PCE_SIZE];
81	uint8_t *extradata;
82
83	if (!hdr.chan_config) {
84	init_get_bits(&gb, in->data, in->size * 8);
85	if (get_bits(&gb, 3) != 5) {
86	avpriv_report_missing_feature(bsfc,
87	"PCE-based channel configuration "
88	"without PCE as first syntax "
89	"element");
90	ret = AVERROR_PATCHWELCOME;
91	goto fail;
92	}
93	init_put_bits(&pb, pce_data, MAX_PCE_SIZE);
94	pce_size = avpriv_copy_pce_data(&pb, &gb)/8;
95	flush_put_bits(&pb);
96	in->size -= get_bits_count(&gb)/8;
97	in->data += get_bits_count(&gb)/8;
98	}
99
100	extradata = av_mallocz(2 + pce_size + AV_INPUT_BUFFER_PADDING_SIZE);
101	if (!extradata) {
102	ret = AVERROR(ENOMEM);
103	goto fail;
104	}
105
106	init_put_bits(&pb, extradata, 2 + pce_size);
107	put_bits(&pb, 5, hdr.object_type);
108	put_bits(&pb, 4, hdr.sampling_index);
109	put_bits(&pb, 4, hdr.chan_config);
110	put_bits(&pb, 1, 0); //frame length - 1024 samples
111	put_bits(&pb, 1, 0); //does not depend on core coder
112	put_bits(&pb, 1, 0); //is not extension
113	flush_put_bits(&pb);
114	if (pce_size) {
115	memcpy(extradata + 2, pce_data, pce_size);
116	}
117
118	bsfc->par_out->extradata = extradata;
119	bsfc->par_out->extradata_size = 2 + pce_size;
120	ctx->first_frame_done = 1;
121	}
122
123	finish:
124	av_packet_move_ref(out, in);
125	av_packet_free(&in);
126
127	return 0;
128
129	packet_too_small:
130	av_log(bsfc, AV_LOG_ERROR, "Input packet too small\n");
131	ret = AVERROR_INVALIDDATA;
132	fail:
133	av_packet_free(&in);
134	return ret;
135	}
136
137	static int aac_adtstoasc_init(AVBSFContext *ctx)
138	{
139	/* Validate the extradata if the stream is already MPEG-4 AudioSpecificConfig */
140	if (ctx->par_in->extradata) {
141	MPEG4AudioConfig mp4ac;
142	int ret = avpriv_mpeg4audio_get_config(&mp4ac, ctx->par_in->extradata,
143	ctx->par_in->extradata_size * 8, 1);
144	if (ret < 0) {
145	av_log(ctx, AV_LOG_ERROR, "Error parsing AudioSpecificConfig extradata!\n");
146	return ret;
147	}
148	}
149
150	return 0;
151	}
152
153	static const enum AVCodecID codec_ids[] = {
154	AV_CODEC_ID_AAC, AV_CODEC_ID_NONE,
155	};
156
157	const AVBitStreamFilter ff_aac_adtstoasc_bsf = {
158	.name = "aac_adtstoasc",
159	.priv_data_size = sizeof(AACBSFContext),
160	.init = aac_adtstoasc_init,
161	.filter = aac_adtstoasc_filter,
162	.codec_ids = codec_ids,
163	};
164