FFmpeg 5.1.4
remuxing.c
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1/*
2 * Copyright (c) 2013 Stefano Sabatini
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 * THE SOFTWARE.
21 */
22
23/**
24 * @file
25 * libavformat/libavcodec demuxing and muxing API example.
26 *
27 * Remux streams from one container format to another.
28 * @example remuxing.c
29 */
30
31#include <libavutil/timestamp.h>
33
34static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag)
35{
37
38 printf("%s: pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
39 tag,
40 av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
41 av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
44}
45
46int main(int argc, char **argv)
47{
48 const AVOutputFormat *ofmt = NULL;
49 AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
50 AVPacket *pkt = NULL;
51 const char *in_filename, *out_filename;
52 int ret, i;
53 int stream_index = 0;
54 int *stream_mapping = NULL;
55 int stream_mapping_size = 0;
56
57 if (argc < 3) {
58 printf("usage: %s input output\n"
59 "API example program to remux a media file with libavformat and libavcodec.\n"
60 "The output format is guessed according to the file extension.\n"
61 "\n", argv[0]);
62 return 1;
63 }
64
65 in_filename = argv[1];
66 out_filename = argv[2];
67
69 if (!pkt) {
70 fprintf(stderr, "Could not allocate AVPacket\n");
71 return 1;
72 }
73
74 if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
75 fprintf(stderr, "Could not open input file '%s'", in_filename);
76 goto end;
77 }
78
79 if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
80 fprintf(stderr, "Failed to retrieve input stream information");
81 goto end;
82 }
83
84 av_dump_format(ifmt_ctx, 0, in_filename, 0);
85
86 avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
87 if (!ofmt_ctx) {
88 fprintf(stderr, "Could not create output context\n");
89 ret = AVERROR_UNKNOWN;
90 goto end;
91 }
92
93 stream_mapping_size = ifmt_ctx->nb_streams;
94 stream_mapping = av_calloc(stream_mapping_size, sizeof(*stream_mapping));
95 if (!stream_mapping) {
96 ret = AVERROR(ENOMEM);
97 goto end;
98 }
99
100 ofmt = ofmt_ctx->oformat;
101
102 for (i = 0; i < ifmt_ctx->nb_streams; i++) {
103 AVStream *out_stream;
104 AVStream *in_stream = ifmt_ctx->streams[i];
105 AVCodecParameters *in_codecpar = in_stream->codecpar;
106
107 if (in_codecpar->codec_type != AVMEDIA_TYPE_AUDIO &&
108 in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO &&
109 in_codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
110 stream_mapping[i] = -1;
111 continue;
112 }
113
114 stream_mapping[i] = stream_index++;
115
116 out_stream = avformat_new_stream(ofmt_ctx, NULL);
117 if (!out_stream) {
118 fprintf(stderr, "Failed allocating output stream\n");
119 ret = AVERROR_UNKNOWN;
120 goto end;
121 }
122
123 ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
124 if (ret < 0) {
125 fprintf(stderr, "Failed to copy codec parameters\n");
126 goto end;
127 }
128 out_stream->codecpar->codec_tag = 0;
129 }
130 av_dump_format(ofmt_ctx, 0, out_filename, 1);
131
132 if (!(ofmt->flags & AVFMT_NOFILE)) {
133 ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
134 if (ret < 0) {
135 fprintf(stderr, "Could not open output file '%s'", out_filename);
136 goto end;
137 }
138 }
139
140 ret = avformat_write_header(ofmt_ctx, NULL);
141 if (ret < 0) {
142 fprintf(stderr, "Error occurred when opening output file\n");
143 goto end;
144 }
145
146 while (1) {
147 AVStream *in_stream, *out_stream;
148
149 ret = av_read_frame(ifmt_ctx, pkt);
150 if (ret < 0)
151 break;
152
153 in_stream = ifmt_ctx->streams[pkt->stream_index];
154 if (pkt->stream_index >= stream_mapping_size ||
155 stream_mapping[pkt->stream_index] < 0) {
157 continue;
158 }
159
160 pkt->stream_index = stream_mapping[pkt->stream_index];
161 out_stream = ofmt_ctx->streams[pkt->stream_index];
162 log_packet(ifmt_ctx, pkt, "in");
163
164 /* copy packet */
165 av_packet_rescale_ts(pkt, in_stream->time_base, out_stream->time_base);
166 pkt->pos = -1;
167 log_packet(ofmt_ctx, pkt, "out");
168
170 /* pkt is now blank (av_interleaved_write_frame() takes ownership of
171 * its contents and resets pkt), so that no unreferencing is necessary.
172 * This would be different if one used av_write_frame(). */
173 if (ret < 0) {
174 fprintf(stderr, "Error muxing packet\n");
175 break;
176 }
177 }
178
180end:
182
184
185 /* close output */
186 if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
189
190 av_freep(&stream_mapping);
191
192 if (ret < 0 && ret != AVERROR_EOF) {
193 fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
194 return 1;
195 }
196
197 return 0;
198}
Main libavformat public API header.
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:470
int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
int avio_open(AVIOContext **s, const char *url, int flags)
Create and initialize a AVIOContext for accessing the resource indicated by url.
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:629
int avio_closep(AVIOContext **s)
Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL...
int avcodec_parameters_copy(AVCodecParameters *dst, const AVCodecParameters *src)
Copy the contents of src to dst.
static AVPacket * pkt
static AVFormatContext * fmt_ctx
void av_packet_free(AVPacket **pkt)
Free the packet, if the packet is reference counted, it will be unreferenced first.
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
AVPacket * av_packet_alloc(void)
Allocate an AVPacket and set its fields to default values.
void av_packet_rescale_ts(AVPacket *pkt, AVRational tb_src, AVRational tb_dst)
Convert valid timing fields (timestamps / durations) in a packet from one timebase to another.
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
int avformat_open_input(AVFormatContext **ps, const char *url, const AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
Read packets of a media file to get stream information.
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
av_warn_unused_result int avformat_write_header(AVFormatContext *s, AVDictionary **options)
Allocate the stream private data and write the stream header to an output media file.
int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file ensuring correct interleaving.
int av_write_trailer(AVFormatContext *s)
Write the stream trailer to an output media file and free the file private data.
void av_dump_format(AVFormatContext *ic, int index, const char *url, int is_output)
Print detailed information about the input or output format, such as duration, bitrate,...
#define AVERROR_UNKNOWN
Unknown error, typically from an external library.
Definition: error.h:73
#define AVERROR_EOF
End of file.
Definition: error.h:57
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:121
#define AVERROR(e)
Definition: error.h:45
void av_freep(void *ptr)
Free a memory block which has been allocated with a function of av_malloc() or av_realloc() family,...
void * av_calloc(size_t nmemb, size_t size) av_malloc_attrib
Allocate a memory block for an array with av_mallocz().
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
int main(int argc, char **argv)
Definition: remuxing.c:46
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag)
Definition: remuxing.c:34
This struct describes the properties of an encoded stream.
Definition: codec_par.h:53
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:57
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: codec_par.h:65
Format I/O context.
Definition: avformat.h:1213
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1269
AVIOContext * pb
I/O context.
Definition: avformat.h:1255
const struct AVOutputFormat * oformat
The output container format.
Definition: avformat.h:1232
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1281
int flags
can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS,...
Definition: avformat.h:529
This structure stores compressed data.
Definition: packet.h:351
int stream_index
Definition: packet.h:376
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:392
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:367
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.
Definition: packet.h:373
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:394
Rational number (pair of numerator and denominator).
Definition: rational.h:58
Stream structure.
Definition: avformat.h:948
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1108
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avformat.h:978
timestamp utils, mostly useful for debugging/logging purposes
#define av_ts2str(ts)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: timestamp.h:54
#define av_ts2timestr(ts, tb)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: timestamp.h:76
static AVFormatContext * ifmt_ctx
Definition: transcoding.c:39
static AVFormatContext * ofmt_ctx
Definition: transcoding.c:40