2 * Copyright (c) 2012 Stefano Sabatini
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5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
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9 * furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice shall be included in
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15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 * Demuxing and decoding example.
27 * Show how to use the libavformat and libavcodec API to demux and
28 * decode audio and video data.
29 * @example demuxing_decoding.c
32 #include <libavutil/imgutils.h>
33 #include <libavutil/samplefmt.h>
34 #include <libavutil/timestamp.h>
35 #include <libavformat/avformat.h>
37 static AVFormatContext
*fmt_ctx
= NULL
;
38 static AVCodecContext
*video_dec_ctx
= NULL
, *audio_dec_ctx
;
39 static AVStream
*video_stream
= NULL
, *audio_stream
= NULL
;
40 static const char *src_filename
= NULL
;
41 static const char *video_dst_filename
= NULL
;
42 static const char *audio_dst_filename
= NULL
;
43 static FILE *video_dst_file
= NULL
;
44 static FILE *audio_dst_file
= NULL
;
46 static uint8_t *video_dst_data
[4] = {NULL
};
47 static int video_dst_linesize
[4];
48 static int video_dst_bufsize
;
50 static int video_stream_idx
= -1, audio_stream_idx
= -1;
51 static AVFrame
*frame
= NULL
;
53 static int video_frame_count
= 0;
54 static int audio_frame_count
= 0;
56 /* The different ways of decoding and managing data memory. You are not
57 * supposed to support all the modes in your application but pick the one most
58 * appropriate to your needs. Look for the use of api_mode in this example to
59 * see what are the differences of API usage between them */
61 API_MODE_OLD
= 0, /* old method, deprecated */
62 API_MODE_NEW_API_REF_COUNT
= 1, /* new method, using the frame reference counting */
63 API_MODE_NEW_API_NO_REF_COUNT
= 2, /* new method, without reference counting */
66 static int api_mode
= API_MODE_OLD
;
68 static int decode_packet(int *got_frame
, int cached
)
71 int decoded
= pkt
.size
;
75 if (pkt
.stream_index
== video_stream_idx
) {
76 /* decode video frame */
77 ret
= avcodec_decode_video2(video_dec_ctx
, frame
, got_frame
, &pkt
);
79 fprintf(stderr
, "Error decoding video frame (%s)\n", av_err2str(ret
));
84 printf("video_frame%s n:%d coded_n:%d pts:%s\n",
85 cached
? "(cached)" : "",
86 video_frame_count
++, frame
->coded_picture_number
,
87 av_ts2timestr(frame
->pts
, &video_dec_ctx
->time_base
));
89 /* copy decoded frame to destination buffer:
90 * this is required since rawvideo expects non aligned data */
91 av_image_copy(video_dst_data
, video_dst_linesize
,
92 (const uint8_t **)(frame
->data
), frame
->linesize
,
93 video_dec_ctx
->pix_fmt
, video_dec_ctx
->width
, video_dec_ctx
->height
);
95 /* write to rawvideo file */
96 fwrite(video_dst_data
[0], 1, video_dst_bufsize
, video_dst_file
);
98 } else if (pkt
.stream_index
== audio_stream_idx
) {
99 /* decode audio frame */
100 ret
= avcodec_decode_audio4(audio_dec_ctx
, frame
, got_frame
, &pkt
);
102 fprintf(stderr
, "Error decoding audio frame (%s)\n", av_err2str(ret
));
105 /* Some audio decoders decode only part of the packet, and have to be
106 * called again with the remainder of the packet data.
107 * Sample: fate-suite/lossless-audio/luckynight-partial.shn
108 * Also, some decoders might over-read the packet. */
109 decoded
= FFMIN(ret
, pkt
.size
);
112 size_t unpadded_linesize
= frame
->nb_samples
* av_get_bytes_per_sample(frame
->format
);
113 printf("audio_frame%s n:%d nb_samples:%d pts:%s\n",
114 cached
? "(cached)" : "",
115 audio_frame_count
++, frame
->nb_samples
,
116 av_ts2timestr(frame
->pts
, &audio_dec_ctx
->time_base
));
118 /* Write the raw audio data samples of the first plane. This works
119 * fine for packed formats (e.g. AV_SAMPLE_FMT_S16). However,
120 * most audio decoders output planar audio, which uses a separate
121 * plane of audio samples for each channel (e.g. AV_SAMPLE_FMT_S16P).
122 * In other words, this code will write only the first audio channel
124 * You should use libswresample or libavfilter to convert the frame
126 fwrite(frame
->extended_data
[0], 1, unpadded_linesize
, audio_dst_file
);
130 /* If we use the new API with reference counting, we own the data and need
131 * to de-reference it when we don't use it anymore */
132 if (*got_frame
&& api_mode
== API_MODE_NEW_API_REF_COUNT
)
133 av_frame_unref(frame
);
138 static int open_codec_context(int *stream_idx
,
139 AVFormatContext
*fmt_ctx
, enum AVMediaType type
)
143 AVCodecContext
*dec_ctx
= NULL
;
145 AVDictionary
*opts
= NULL
;
147 ret
= av_find_best_stream(fmt_ctx
, type
, -1, -1, NULL
, 0);
149 fprintf(stderr
, "Could not find %s stream in input file '%s'\n",
150 av_get_media_type_string(type
), src_filename
);
154 st
= fmt_ctx
->streams
[*stream_idx
];
156 /* find decoder for the stream */
158 dec
= avcodec_find_decoder(dec_ctx
->codec_id
);
160 fprintf(stderr
, "Failed to find %s codec\n",
161 av_get_media_type_string(type
));
162 return AVERROR(EINVAL
);
165 /* Init the decoders, with or without reference counting */
166 if (api_mode
== API_MODE_NEW_API_REF_COUNT
)
167 av_dict_set(&opts
, "refcounted_frames", "1", 0);
168 if ((ret
= avcodec_open2(dec_ctx
, dec
, &opts
)) < 0) {
169 fprintf(stderr
, "Failed to open %s codec\n",
170 av_get_media_type_string(type
));
178 static int get_format_from_sample_fmt(const char **fmt
,
179 enum AVSampleFormat sample_fmt
)
182 struct sample_fmt_entry
{
183 enum AVSampleFormat sample_fmt
; const char *fmt_be
, *fmt_le
;
184 } sample_fmt_entries
[] = {
185 { AV_SAMPLE_FMT_U8
, "u8", "u8" },
186 { AV_SAMPLE_FMT_S16
, "s16be", "s16le" },
187 { AV_SAMPLE_FMT_S32
, "s32be", "s32le" },
188 { AV_SAMPLE_FMT_FLT
, "f32be", "f32le" },
189 { AV_SAMPLE_FMT_DBL
, "f64be", "f64le" },
193 for (i
= 0; i
< FF_ARRAY_ELEMS(sample_fmt_entries
); i
++) {
194 struct sample_fmt_entry
*entry
= &sample_fmt_entries
[i
];
195 if (sample_fmt
== entry
->sample_fmt
) {
196 *fmt
= AV_NE(entry
->fmt_be
, entry
->fmt_le
);
202 "sample format %s is not supported as output format\n",
203 av_get_sample_fmt_name(sample_fmt
));
207 int main (int argc
, char **argv
)
209 int ret
= 0, got_frame
;
211 if (argc
!= 4 && argc
!= 5) {
212 fprintf(stderr
, "usage: %s [-refcount=<old|new_norefcount|new_refcount>] "
213 "input_file video_output_file audio_output_file\n"
214 "API example program to show how to read frames from an input file.\n"
215 "This program reads frames from a file, decodes them, and writes decoded\n"
216 "video frames to a rawvideo file named video_output_file, and decoded\n"
217 "audio frames to a rawaudio file named audio_output_file.\n\n"
218 "If the -refcount option is specified, the program use the\n"
219 "reference counting frame system which allows keeping a copy of\n"
220 "the data for longer than one decode call. If unset, it's using\n"
221 "the classic old method.\n"
226 const char *mode
= argv
[1] + strlen("-refcount=");
227 if (!strcmp(mode
, "old")) api_mode
= API_MODE_OLD
;
228 else if (!strcmp(mode
, "new_norefcount")) api_mode
= API_MODE_NEW_API_NO_REF_COUNT
;
229 else if (!strcmp(mode
, "new_refcount")) api_mode
= API_MODE_NEW_API_REF_COUNT
;
231 fprintf(stderr
, "unknow mode '%s'\n", mode
);
236 src_filename
= argv
[1];
237 video_dst_filename
= argv
[2];
238 audio_dst_filename
= argv
[3];
240 /* register all formats and codecs */
243 /* open input file, and allocate format context */
244 if (avformat_open_input(&fmt_ctx
, src_filename
, NULL
, NULL
) < 0) {
245 fprintf(stderr
, "Could not open source file %s\n", src_filename
);
249 /* retrieve stream information */
250 if (avformat_find_stream_info(fmt_ctx
, NULL
) < 0) {
251 fprintf(stderr
, "Could not find stream information\n");
255 if (open_codec_context(&video_stream_idx
, fmt_ctx
, AVMEDIA_TYPE_VIDEO
) >= 0) {
256 video_stream
= fmt_ctx
->streams
[video_stream_idx
];
257 video_dec_ctx
= video_stream
->codec
;
259 video_dst_file
= fopen(video_dst_filename
, "wb");
260 if (!video_dst_file
) {
261 fprintf(stderr
, "Could not open destination file %s\n", video_dst_filename
);
266 /* allocate image where the decoded image will be put */
267 ret
= av_image_alloc(video_dst_data
, video_dst_linesize
,
268 video_dec_ctx
->width
, video_dec_ctx
->height
,
269 video_dec_ctx
->pix_fmt
, 1);
271 fprintf(stderr
, "Could not allocate raw video buffer\n");
274 video_dst_bufsize
= ret
;
277 if (open_codec_context(&audio_stream_idx
, fmt_ctx
, AVMEDIA_TYPE_AUDIO
) >= 0) {
278 audio_stream
= fmt_ctx
->streams
[audio_stream_idx
];
279 audio_dec_ctx
= audio_stream
->codec
;
280 audio_dst_file
= fopen(audio_dst_filename
, "wb");
281 if (!audio_dst_file
) {
282 fprintf(stderr
, "Could not open destination file %s\n", audio_dst_filename
);
288 /* dump input information to stderr */
289 av_dump_format(fmt_ctx
, 0, src_filename
, 0);
291 if (!audio_stream
&& !video_stream
) {
292 fprintf(stderr
, "Could not find audio or video stream in the input, aborting\n");
297 /* When using the new API, you need to use the libavutil/frame.h API, while
298 * the classic frame management is available in libavcodec */
299 if (api_mode
== API_MODE_OLD
)
300 frame
= avcodec_alloc_frame();
302 frame
= av_frame_alloc();
304 fprintf(stderr
, "Could not allocate frame\n");
305 ret
= AVERROR(ENOMEM
);
309 /* initialize packet, set data to NULL, let the demuxer fill it */
310 av_init_packet(&pkt
);
315 printf("Demuxing video from file '%s' into '%s'\n", src_filename
, video_dst_filename
);
317 printf("Demuxing audio from file '%s' into '%s'\n", src_filename
, audio_dst_filename
);
319 /* read frames from the file */
320 while (av_read_frame(fmt_ctx
, &pkt
) >= 0) {
321 AVPacket orig_pkt
= pkt
;
323 ret
= decode_packet(&got_frame
, 0);
328 } while (pkt
.size
> 0);
329 av_free_packet(&orig_pkt
);
332 /* flush cached frames */
336 decode_packet(&got_frame
, 1);
339 printf("Demuxing succeeded.\n");
342 printf("Play the output video file with the command:\n"
343 "ffplay -f rawvideo -pix_fmt %s -video_size %dx%d %s\n",
344 av_get_pix_fmt_name(video_dec_ctx
->pix_fmt
), video_dec_ctx
->width
, video_dec_ctx
->height
,
349 enum AVSampleFormat sfmt
= audio_dec_ctx
->sample_fmt
;
350 int n_channels
= audio_dec_ctx
->channels
;
353 if (av_sample_fmt_is_planar(sfmt
)) {
354 const char *packed
= av_get_sample_fmt_name(sfmt
);
355 printf("Warning: the sample format the decoder produced is planar "
356 "(%s). This example will output the first channel only.\n",
357 packed
? packed
: "?");
358 sfmt
= av_get_packed_sample_fmt(sfmt
);
362 if ((ret
= get_format_from_sample_fmt(&fmt
, sfmt
)) < 0)
365 printf("Play the output audio file with the command:\n"
366 "ffplay -f %s -ac %d -ar %d %s\n",
367 fmt
, n_channels
, audio_dec_ctx
->sample_rate
,
372 avcodec_close(video_dec_ctx
);
373 avcodec_close(audio_dec_ctx
);
374 avformat_close_input(&fmt_ctx
);
376 fclose(video_dst_file
);
378 fclose(audio_dst_file
);
379 if (api_mode
== API_MODE_OLD
)
380 avcodec_free_frame(&frame
);
382 av_frame_free(&frame
);
383 av_free(video_dst_data
[0]);