1 /*
2 * AST muxer
3 * Copyright (c) 2012 James Almer
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 "avformat.h"
23 #include "avio_internal.h"
24 #include "internal.h"
25 #include "ast.h"
26 #include "libavutil/mathematics.h"
27 #include "libavutil/opt.h"
28
29 typedef struct ASTMuxContext {
30 AVClass *class;
31 int64_t size;
32 int64_t samples;
33 int64_t loopstart;
34 int64_t loopend;
35 int fbs;
36 } ASTMuxContext;
37
38 #define CHECK_LOOP(type) \
39 if (ast->loop ## type > 0) { \
40 ast->loop ## type = av_rescale_rnd(ast->loop ## type, par->sample_rate, 1000, AV_ROUND_DOWN); \
41 if (ast->loop ## type < 0 || ast->loop ## type > UINT_MAX) { \
42 av_log(s, AV_LOG_ERROR, "Invalid loop" #type " value\n"); \
43 return AVERROR(EINVAL); \
44 } \
45 }
46
ast_write_header(AVFormatContext * s)47 static int ast_write_header(AVFormatContext *s)
48 {
49 ASTMuxContext *ast = s->priv_data;
50 AVIOContext *pb = s->pb;
51 AVCodecParameters *par;
52 unsigned int codec_tag;
53
54 if (s->nb_streams == 1) {
55 par = s->streams[0]->codecpar;
56 } else {
57 av_log(s, AV_LOG_ERROR, "only one stream is supported\n");
58 return AVERROR(EINVAL);
59 }
60
61 if (par->codec_id == AV_CODEC_ID_ADPCM_AFC) {
62 av_log(s, AV_LOG_ERROR, "muxing ADPCM AFC is not implemented\n");
63 return AVERROR_PATCHWELCOME;
64 }
65
66 codec_tag = ff_codec_get_tag(ff_codec_ast_tags, par->codec_id);
67 if (!codec_tag) {
68 av_log(s, AV_LOG_ERROR, "unsupported codec\n");
69 return AVERROR(EINVAL);
70 }
71
72 if (ast->loopend > 0 && ast->loopstart >= ast->loopend) {
73 av_log(s, AV_LOG_ERROR, "loopend can't be less or equal to loopstart\n");
74 return AVERROR(EINVAL);
75 }
76
77 /* Convert milliseconds to samples */
78 CHECK_LOOP(start)
79 CHECK_LOOP(end)
80
81 ffio_wfourcc(pb, "STRM");
82
83 ast->size = avio_tell(pb);
84 avio_wb32(pb, 0); /* File size minus header */
85 avio_wb16(pb, codec_tag);
86 avio_wb16(pb, 16); /* Bit depth */
87 avio_wb16(pb, par->ch_layout.nb_channels);
88 avio_wb16(pb, 0); /* Loop flag */
89 avio_wb32(pb, par->sample_rate);
90
91 ast->samples = avio_tell(pb);
92 avio_wb32(pb, 0); /* Number of samples */
93 avio_wb32(pb, 0); /* Loopstart */
94 avio_wb32(pb, 0); /* Loopend */
95 avio_wb32(pb, 0); /* Size of first block */
96
97 /* Unknown */
98 avio_wb32(pb, 0);
99 avio_wl32(pb, 0x7F);
100 avio_wb64(pb, 0);
101 avio_wb64(pb, 0);
102 avio_wb32(pb, 0);
103
104 return 0;
105 }
106
ast_write_packet(AVFormatContext * s,AVPacket * pkt)107 static int ast_write_packet(AVFormatContext *s, AVPacket *pkt)
108 {
109 AVIOContext *pb = s->pb;
110 ASTMuxContext *ast = s->priv_data;
111 AVCodecParameters *par = s->streams[0]->codecpar;
112 int size = pkt->size / par->ch_layout.nb_channels;
113
114 if (s->streams[0]->nb_frames == 0)
115 ast->fbs = size;
116
117 ffio_wfourcc(pb, "BLCK");
118 avio_wb32(pb, size); /* Block size */
119
120 /* padding */
121 ffio_fill(pb, 0, 24);
122
123 avio_write(pb, pkt->data, pkt->size);
124
125 return 0;
126 }
127
ast_write_trailer(AVFormatContext * s)128 static int ast_write_trailer(AVFormatContext *s)
129 {
130 AVIOContext *pb = s->pb;
131 ASTMuxContext *ast = s->priv_data;
132 AVCodecParameters *par = s->streams[0]->codecpar;
133 int64_t file_size = avio_tell(pb);
134 int64_t samples = (file_size - 64 - (32 * s->streams[0]->nb_frames)) / par->block_align; /* PCM_S16BE_PLANAR */
135
136 av_log(s, AV_LOG_DEBUG, "total samples: %"PRId64"\n", samples);
137
138 if (s->pb->seekable & AVIO_SEEKABLE_NORMAL) {
139 /* Number of samples */
140 avio_seek(pb, ast->samples, SEEK_SET);
141 avio_wb32(pb, samples);
142
143 /* Loopstart if provided */
144 if (ast->loopstart > 0) {
145 if (ast->loopstart >= samples) {
146 av_log(s, AV_LOG_WARNING, "Loopstart value is out of range and will be ignored\n");
147 ast->loopstart = -1;
148 avio_skip(pb, 4);
149 } else
150 avio_wb32(pb, ast->loopstart);
151 } else
152 avio_skip(pb, 4);
153
154 /* Loopend if provided. Otherwise number of samples again */
155 if (ast->loopend && ast->loopstart >= 0) {
156 if (ast->loopend > samples) {
157 av_log(s, AV_LOG_WARNING, "Loopend value is out of range and will be ignored\n");
158 ast->loopend = samples;
159 }
160 avio_wb32(pb, ast->loopend);
161 } else {
162 avio_wb32(pb, samples);
163 }
164
165 /* Size of first block */
166 avio_wb32(pb, ast->fbs);
167
168 /* File size minus header */
169 avio_seek(pb, ast->size, SEEK_SET);
170 avio_wb32(pb, file_size - 64);
171
172 /* Loop flag */
173 if (ast->loopstart >= 0) {
174 avio_skip(pb, 6);
175 avio_wb16(pb, 0xFFFF);
176 }
177
178 avio_seek(pb, file_size, SEEK_SET);
179 }
180 return 0;
181 }
182
183 #define OFFSET(obj) offsetof(ASTMuxContext, obj)
184 static const AVOption options[] = {
185 { "loopstart", "Loopstart position in milliseconds.", OFFSET(loopstart), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
186 { "loopend", "Loopend position in milliseconds.", OFFSET(loopend), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
187 { NULL },
188 };
189
190 static const AVClass ast_muxer_class = {
191 .class_name = "AST muxer",
192 .item_name = av_default_item_name,
193 .option = options,
194 .version = LIBAVUTIL_VERSION_INT,
195 };
196
197 const AVOutputFormat ff_ast_muxer = {
198 .name = "ast",
199 .long_name = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
200 .extensions = "ast",
201 .priv_data_size = sizeof(ASTMuxContext),
202 .audio_codec = AV_CODEC_ID_PCM_S16BE_PLANAR,
203 .video_codec = AV_CODEC_ID_NONE,
204 .write_header = ast_write_header,
205 .write_packet = ast_write_packet,
206 .write_trailer = ast_write_trailer,
207 .priv_class = &ast_muxer_class,
208 .codec_tag = ff_ast_codec_tags_list,
209 };
210