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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>
32 #include <libavformat/avformat.h>
33 
34 static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag)
35 {
36  AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
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),
42  av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
43  pkt->stream_index);
44 }
45 
46 int main(int argc, char **argv)
47 {
48  AVOutputFormat *ofmt = NULL;
50  AVPacket pkt;
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 
68  if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
69  fprintf(stderr, "Could not open input file '%s'", in_filename);
70  goto end;
71  }
72 
73  if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
74  fprintf(stderr, "Failed to retrieve input stream information");
75  goto end;
76  }
77 
78  av_dump_format(ifmt_ctx, 0, in_filename, 0);
79 
80  avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
81  if (!ofmt_ctx) {
82  fprintf(stderr, "Could not create output context\n");
83  ret = AVERROR_UNKNOWN;
84  goto end;
85  }
86 
87  stream_mapping_size = ifmt_ctx->nb_streams;
88  stream_mapping = av_mallocz_array(stream_mapping_size, sizeof(*stream_mapping));
89  if (!stream_mapping) {
90  ret = AVERROR(ENOMEM);
91  goto end;
92  }
93 
94  ofmt = ofmt_ctx->oformat;
95 
96  for (i = 0; i < ifmt_ctx->nb_streams; i++) {
97  AVStream *out_stream;
98  AVStream *in_stream = ifmt_ctx->streams[i];
99  AVCodecParameters *in_codecpar = in_stream->codecpar;
100 
101  if (in_codecpar->codec_type != AVMEDIA_TYPE_AUDIO &&
102  in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO &&
103  in_codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
104  stream_mapping[i] = -1;
105  continue;
106  }
107 
108  stream_mapping[i] = stream_index++;
109 
110  out_stream = avformat_new_stream(ofmt_ctx, NULL);
111  if (!out_stream) {
112  fprintf(stderr, "Failed allocating output stream\n");
113  ret = AVERROR_UNKNOWN;
114  goto end;
115  }
116 
117  ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
118  if (ret < 0) {
119  fprintf(stderr, "Failed to copy codec parameters\n");
120  goto end;
121  }
122  out_stream->codecpar->codec_tag = 0;
123  }
124  av_dump_format(ofmt_ctx, 0, out_filename, 1);
125 
126  if (!(ofmt->flags & AVFMT_NOFILE)) {
127  ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
128  if (ret < 0) {
129  fprintf(stderr, "Could not open output file '%s'", out_filename);
130  goto end;
131  }
132  }
133 
134  ret = avformat_write_header(ofmt_ctx, NULL);
135  if (ret < 0) {
136  fprintf(stderr, "Error occurred when opening output file\n");
137  goto end;
138  }
139 
140  while (1) {
141  AVStream *in_stream, *out_stream;
142 
143  ret = av_read_frame(ifmt_ctx, &pkt);
144  if (ret < 0)
145  break;
146 
147  in_stream = ifmt_ctx->streams[pkt.stream_index];
148  if (pkt.stream_index >= stream_mapping_size ||
149  stream_mapping[pkt.stream_index] < 0) {
150  av_packet_unref(&pkt);
151  continue;
152  }
153 
154  pkt.stream_index = stream_mapping[pkt.stream_index];
155  out_stream = ofmt_ctx->streams[pkt.stream_index];
156  log_packet(ifmt_ctx, &pkt, "in");
157 
158  /* copy packet */
161  pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
162  pkt.pos = -1;
163  log_packet(ofmt_ctx, &pkt, "out");
164 
165  ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
166  if (ret < 0) {
167  fprintf(stderr, "Error muxing packet\n");
168  break;
169  }
170  av_packet_unref(&pkt);
171  }
172 
173  av_write_trailer(ofmt_ctx);
174 end:
175 
176  avformat_close_input(&ifmt_ctx);
177 
178  /* close output */
179  if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
180  avio_closep(&ofmt_ctx->pb);
181  avformat_free_context(ofmt_ctx);
182 
183  av_freep(&stream_mapping);
184 
185  if (ret < 0 && ret != AVERROR_EOF) {
186  fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
187  return 1;
188  }
189 
190  return 0;
191 }
int avio_open(AVIOContext **s, const char *url, int flags)
Create and initialize a AVIOContext for accessing the resource indicated by url.
Definition: aviobuf.c:1154
#define NULL
Definition: coverity.c:32
int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file ensuring correct interleaving.
Definition: mux.c:1185
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1451
static AVFormatContext * fmt_ctx
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:655
static AVPacket pkt
This struct describes the properties of an encoded stream.
Definition: avcodec.h:3877
int main(int argc, char **argv)
Definition: remuxing.c:46
Format I/O context.
Definition: avformat.h:1351
int flags
can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS, AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH, AVFMT_TS_NONSTRICT, AVFMT_TS_NEGATIVE
Definition: avformat.h:526
timestamp utils, mostly useful for debugging/logging purposes
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1449
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4456
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1419
uint32_t tag
Definition: movenc.c:1465
#define AVERROR_EOF
End of file.
Definition: error.h:55
int avformat_alloc_output_context2(AVFormatContext **ctx, AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
Definition: mux.c:148
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:142
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, streams, container, programs, metadata, side data, codec and time base.
Definition: dump.c:563
int avcodec_parameters_copy(AVCodecParameters *dst, const AVCodecParameters *src)
Copy the contents of src to dst.
Definition: utils.c:2003
static AVFormatContext * ifmt_ctx
Definition: transcoding.c:38
#define AVERROR(e)
Definition: error.h:43
#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
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3881
Round to nearest and halfway cases away from zero.
Definition: mathematics.h:84
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1407
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.
Definition: mux.c:508
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:119
Stream structure.
Definition: avformat.h:874
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag)
Definition: remuxing.c:34
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:592
Rational number (pair of numerator and denominator).
Definition: rational.h:58
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: utils.c:4390
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: utils.c:1767
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:465
int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
Read packets of a media file to get stream information.
Definition: utils.c:3565
#define AVERROR_UNKNOWN
Unknown error, typically from an external library.
Definition: error.h:71
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
Definition: utils.c:4428
Flag telling rescaling functions to pass INT64_MIN/MAX through unchanged, avoiding special cases for ...
Definition: mathematics.h:108
#define av_ts2str(ts)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: timestamp.h:54
int avformat_open_input(AVFormatContext **ps, const char *url, AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
Definition: utils.c:537
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed...
Definition: avcodec.h:1430
int av_write_trailer(AVFormatContext *s)
Write the stream trailer to an output media file and free the file private data.
Definition: mux.c:1247
#define av_freep(p)
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1021
int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq, enum AVRounding rnd)
Rescale a 64-bit integer by 2 rational numbers with specified rounding.
Definition: mathematics.c:134
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: avcodec.h:3889
int stream_index
Definition: avcodec.h:1433
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:903
This structure stores compressed data.
Definition: avcodec.h:1408
int avio_closep(AVIOContext **s)
Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL...
Definition: aviobuf.c:1215
static AVFormatContext * ofmt_ctx
Definition: transcoding.c:39
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1424
void * av_mallocz_array(size_t nmemb, size_t size)
Definition: mem.c:191