FFmpeg
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:1497
static AVFormatContext * fmt_ctx
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:655
int avformat_open_input(AVFormatContext **ps, const char *url, ff_const59 AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
Definition: utils.c:537
static AVPacket pkt
This struct describes the properties of an encoded stream.
Definition: avcodec.h:3945
int main(int argc, char **argv)
Definition: remuxing.c:46
Format I/O context.
Definition: avformat.h:1358
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:524
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:1495
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4455
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
uint32_t tag
Definition: movenc.c:1496
#define AVERROR_EOF
End of file.
Definition: error.h:55
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
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:260
int avcodec_parameters_copy(AVCodecParameters *dst, const AVCodecParameters *src)
Copy the contents of src to dst.
Definition: utils.c:2013
static AVFormatContext * ifmt_ctx
Definition: transcoding.c:38
#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:3949
Round to nearest and halfway cases away from zero.
Definition: mathematics.h:84
int avformat_alloc_output_context2(AVFormatContext **ctx, ff_const59 AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
Definition: mux.c:148
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1414
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:881
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:599
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:4389
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: utils.c:1768
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:463
int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
Read packets of a media file to get stream information.
Definition: utils.c:3564
#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:4427
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
printf("static const uint8_t my_array[100] = {\n")
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed...
Definition: avcodec.h:1476
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:1028
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:3957
int stream_index
Definition: avcodec.h:1479
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:910
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
This structure stores compressed data.
Definition: avcodec.h:1454
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:1470
void * av_mallocz_array(size_t nmemb, size_t size)
Definition: mem.c:191