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
29typedef 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, enc->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
47static int ast_write_header(AVFormatContext *s)
48{
49    ASTMuxContext *ast = s->priv_data;
50    AVIOContext *pb = s->pb;
51    AVCodecContext *enc;
52    unsigned int codec_tag;
53
54    if (s->nb_streams == 1) {
55        enc = s->streams[0]->codec;
56    } else {
57        av_log(s, AV_LOG_ERROR, "only one stream is supported\n");
58        return AVERROR(EINVAL);
59    }
60
61    if (enc->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, enc->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, enc->channels);
88    avio_wb16(pb, 0); /* Loop flag */
89    avio_wb32(pb, enc->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    avio_flush(pb);
105
106    return 0;
107}
108
109static int ast_write_packet(AVFormatContext *s, AVPacket *pkt)
110{
111    AVIOContext *pb = s->pb;
112    ASTMuxContext *ast = s->priv_data;
113    AVCodecContext *enc = s->streams[0]->codec;
114    int size = pkt->size / enc->channels;
115
116    if (s->streams[0]->nb_frames == 0)
117        ast->fbs = size;
118
119    ffio_wfourcc(pb, "BLCK");
120    avio_wb32(pb, size); /* Block size */
121
122    /* padding */
123    avio_wb64(pb, 0);
124    avio_wb64(pb, 0);
125    avio_wb64(pb, 0);
126
127    avio_write(pb, pkt->data, pkt->size);
128
129    return 0;
130}
131
132static int ast_write_trailer(AVFormatContext *s)
133{
134    AVIOContext *pb = s->pb;
135    ASTMuxContext *ast = s->priv_data;
136    AVCodecContext *enc = s->streams[0]->codec;
137    int64_t file_size = avio_tell(pb);
138    int64_t samples = (file_size - 64 - (32 * s->streams[0]->nb_frames)) / enc->block_align; /* PCM_S16BE_PLANAR */
139
140    av_log(s, AV_LOG_DEBUG, "total samples: %"PRId64"\n", samples);
141
142    if (s->pb->seekable) {
143        /* Number of samples */
144        avio_seek(pb, ast->samples, SEEK_SET);
145        avio_wb32(pb, samples);
146
147        /* Loopstart if provided */
148        if (ast->loopstart > 0) {
149        if (ast->loopstart >= samples) {
150            av_log(s, AV_LOG_WARNING, "Loopstart value is out of range and will be ignored\n");
151            ast->loopstart = -1;
152            avio_skip(pb, 4);
153        } else
154        avio_wb32(pb, ast->loopstart);
155        } else
156            avio_skip(pb, 4);
157
158        /* Loopend if provided. Otherwise number of samples again */
159        if (ast->loopend && ast->loopstart >= 0) {
160            if (ast->loopend > samples) {
161                av_log(s, AV_LOG_WARNING, "Loopend value is out of range and will be ignored\n");
162                ast->loopend = samples;
163            }
164            avio_wb32(pb, ast->loopend);
165        } else {
166            avio_wb32(pb, samples);
167        }
168
169        /* Size of first block */
170        avio_wb32(pb, ast->fbs);
171
172        /* File size minus header */
173        avio_seek(pb, ast->size, SEEK_SET);
174        avio_wb32(pb, file_size - 64);
175
176        /* Loop flag */
177        if (ast->loopstart >= 0) {
178            avio_skip(pb, 6);
179            avio_wb16(pb, 0xFFFF);
180        }
181
182        avio_seek(pb, file_size, SEEK_SET);
183        avio_flush(pb);
184    }
185    return 0;
186}
187
188#define OFFSET(obj) offsetof(ASTMuxContext, obj)
189static const AVOption options[] = {
190  { "loopstart", "Loopstart position in milliseconds.", OFFSET(loopstart), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
191  { "loopend",   "Loopend position in milliseconds.",   OFFSET(loopend),   AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
192  { NULL },
193};
194
195static const AVClass ast_muxer_class = {
196    .class_name = "AST muxer",
197    .item_name  = av_default_item_name,
198    .option     = options,
199    .version    = LIBAVUTIL_VERSION_INT,
200};
201
202AVOutputFormat ff_ast_muxer = {
203    .name              = "ast",
204    .long_name         = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
205    .extensions        = "ast",
206    .priv_data_size    = sizeof(ASTMuxContext),
207    .audio_codec       = AV_CODEC_ID_PCM_S16BE_PLANAR,
208    .video_codec       = AV_CODEC_ID_NONE,
209    .write_header      = ast_write_header,
210    .write_packet      = ast_write_packet,
211    .write_trailer     = ast_write_trailer,
212    .priv_class        = &ast_muxer_class,
213    .codec_tag         = (const AVCodecTag* const []){ff_codec_ast_tags, 0},
214};
215