FFmpeg 7.0.2
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qsv_transcode.c
Go to the documentation of this file.
1/*
2 * Permission is hereby granted, free of charge, to any person obtaining a copy
3 * of this software and associated documentation files (the "Software"), to deal
4 * in the Software without restriction, including without limitation the rights
5 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
6 * copies of the Software, and to permit persons to whom the Software is
7 * furnished to do so, subject to the following conditions:
8 *
9 * The above copyright notice and this permission notice shall be included in
10 * all copies or substantial portions of the Software.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
13 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
14 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
15 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
16 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
17 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
18 * THE SOFTWARE.
19 */
20
21/**
22 * @file Intel QSV-accelerated video transcoding API usage example
23 * @example qsv_transcode.c
24 *
25 * Perform QSV-accelerated transcoding and show to dynamically change
26 * encoder's options.
27 *
28 * Usage: qsv_transcode input_stream codec output_stream initial option
29 * { frame_number new_option }
30 * e.g: - qsv_transcode input.mp4 h264_qsv output_h264.mp4 "g 60"
31 * - qsv_transcode input.mp4 hevc_qsv output_hevc.mp4 "g 60 async_depth 1"
32 * 100 "g 120"
33 * (initialize codec with gop_size 60 and change it to 120 after 100
34 * frames)
35 */
36
37#include <stdio.h>
38#include <errno.h>
39
40#include <libavutil/hwcontext.h>
41#include <libavcodec/avcodec.h>
43#include <libavutil/opt.h>
44
45static AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
47static AVCodecContext *decoder_ctx = NULL, *encoder_ctx = NULL;
48static int video_stream = -1;
49
50typedef struct DynamicSetting {
52 char* optstr;
55static int setting_number;
57
58static int str_to_dict(char* optstr, AVDictionary **opt)
59{
60 char *key, *value;
61 if (strlen(optstr) == 0)
62 return 0;
63 key = strtok(optstr, " ");
64 if (key == NULL)
65 return AVERROR(EINVAL);
66 value = strtok(NULL, " ");
67 if (value == NULL)
68 return AVERROR(EINVAL);
69 av_dict_set(opt, key, value, 0);
70 do {
71 key = strtok(NULL, " ");
72 if (key == NULL)
73 return 0;
74 value = strtok(NULL, " ");
75 if (value == NULL)
76 return AVERROR(EINVAL);
77 av_dict_set(opt, key, value, 0);
78 } while(1);
79}
80
82{
83 AVDictionary *opts = NULL;
84 int ret = 0;
85 static int frame_number = 0;
86 frame_number++;
88 frame_number == dynamic_setting[current_setting_number].frame_number) {
89 AVDictionaryEntry *e = NULL;
91 if (ret < 0) {
92 fprintf(stderr, "The dynamic parameter is wrong\n");
93 goto fail;
94 }
95 /* Set common option. The dictionary will be freed and replaced
96 * by a new one containing all options not found in common option list.
97 * Then this new dictionary is used to set private option. */
98 if ((ret = av_opt_set_dict(avctx, &opts)) < 0)
99 goto fail;
100 /* Set codec specific option */
101 if ((ret = av_opt_set_dict(avctx->priv_data, &opts)) < 0)
102 goto fail;
103 /* There is no "framerate" option in commom option list. Use "-r" to set
104 * framerate, which is compatible with ffmpeg commandline. The video is
105 * assumed to be average frame rate, so set time_base to 1/framerate. */
106 e = av_dict_get(opts, "r", NULL, 0);
107 if (e) {
108 avctx->framerate = av_d2q(atof(e->value), INT_MAX);
110 }
111 }
112fail:
113 av_dict_free(&opts);
114 return ret;
115}
116
117static int get_format(AVCodecContext *avctx, const enum AVPixelFormat *pix_fmts)
118{
119 while (*pix_fmts != AV_PIX_FMT_NONE) {
120 if (*pix_fmts == AV_PIX_FMT_QSV) {
121 return AV_PIX_FMT_QSV;
122 }
123
124 pix_fmts++;
125 }
126
127 fprintf(stderr, "The QSV pixel format not offered in get_format()\n");
128
129 return AV_PIX_FMT_NONE;
130}
131
132static int open_input_file(char *filename)
133{
134 int ret;
135 const AVCodec *decoder = NULL;
136 AVStream *video = NULL;
137
138 if ((ret = avformat_open_input(&ifmt_ctx, filename, NULL, NULL)) < 0) {
139 fprintf(stderr, "Cannot open input file '%s', Error code: %s\n",
140 filename, av_err2str(ret));
141 return ret;
142 }
143
144 if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) {
145 fprintf(stderr, "Cannot find input stream information. Error code: %s\n",
146 av_err2str(ret));
147 return ret;
148 }
149
150 ret = av_find_best_stream(ifmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
151 if (ret < 0) {
152 fprintf(stderr, "Cannot find a video stream in the input file. "
153 "Error code: %s\n", av_err2str(ret));
154 return ret;
155 }
156 video_stream = ret;
157 video = ifmt_ctx->streams[video_stream];
158
159 switch(video->codecpar->codec_id) {
160 case AV_CODEC_ID_H264:
161 decoder = avcodec_find_decoder_by_name("h264_qsv");
162 break;
163 case AV_CODEC_ID_HEVC:
164 decoder = avcodec_find_decoder_by_name("hevc_qsv");
165 break;
166 case AV_CODEC_ID_VP9:
167 decoder = avcodec_find_decoder_by_name("vp9_qsv");
168 break;
169 case AV_CODEC_ID_VP8:
170 decoder = avcodec_find_decoder_by_name("vp8_qsv");
171 break;
172 case AV_CODEC_ID_AV1:
173 decoder = avcodec_find_decoder_by_name("av1_qsv");
174 break;
176 decoder = avcodec_find_decoder_by_name("mpeg2_qsv");
177 break;
179 decoder = avcodec_find_decoder_by_name("mjpeg_qsv");
180 break;
181 default:
182 fprintf(stderr, "Codec is not supportted by qsv\n");
183 return AVERROR(EINVAL);
184 }
185
186 if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
187 return AVERROR(ENOMEM);
188
189 if ((ret = avcodec_parameters_to_context(decoder_ctx, video->codecpar)) < 0) {
190 fprintf(stderr, "avcodec_parameters_to_context error. Error code: %s\n",
191 av_err2str(ret));
192 return ret;
193 }
195
198 fprintf(stderr, "A hardware device reference create failed.\n");
199 return AVERROR(ENOMEM);
200 }
203 if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0)
204 fprintf(stderr, "Failed to open codec for decoding. Error code: %s\n",
205 av_err2str(ret));
206
207 return ret;
208}
209
210static int encode_write(AVPacket *enc_pkt, AVFrame *frame)
211{
212 int ret = 0;
213
214 av_packet_unref(enc_pkt);
215
216 if((ret = dynamic_set_parameter(encoder_ctx)) < 0) {
217 fprintf(stderr, "Failed to set dynamic parameter. Error code: %s\n",
218 av_err2str(ret));
219 goto end;
220 }
221
222 if ((ret = avcodec_send_frame(encoder_ctx, frame)) < 0) {
223 fprintf(stderr, "Error during encoding. Error code: %s\n", av_err2str(ret));
224 goto end;
225 }
226 while (1) {
227 if (ret = avcodec_receive_packet(encoder_ctx, enc_pkt))
228 break;
229 enc_pkt->stream_index = 0;
232 if ((ret = av_interleaved_write_frame(ofmt_ctx, enc_pkt)) < 0) {
233 fprintf(stderr, "Error during writing data to output file. "
234 "Error code: %s\n", av_err2str(ret));
235 return ret;
236 }
237 }
238
239end:
240 if (ret == AVERROR_EOF)
241 return 0;
242 ret = ((ret == AVERROR(EAGAIN)) ? 0:-1);
243 return ret;
244}
245
246static int dec_enc(AVPacket *pkt, const AVCodec *enc_codec, char *optstr)
247{
248 AVFrame *frame;
249 int ret = 0;
250
252 if (ret < 0) {
253 fprintf(stderr, "Error during decoding. Error code: %s\n", av_err2str(ret));
254 return ret;
255 }
256
257 while (ret >= 0) {
258 if (!(frame = av_frame_alloc()))
259 return AVERROR(ENOMEM);
260
262 if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
264 return 0;
265 } else if (ret < 0) {
266 fprintf(stderr, "Error while decoding. Error code: %s\n", av_err2str(ret));
267 goto fail;
268 }
270 AVDictionaryEntry *e = NULL;
271 AVDictionary *opts = NULL;
272 AVStream *ost;
273 /* we need to ref hw_frames_ctx of decoder to initialize encoder's codec.
274 Only after we get a decoded frame, can we obtain its hw_frames_ctx */
277 ret = AVERROR(ENOMEM);
278 goto fail;
279 }
280 /* set AVCodecContext Parameters for encoder, here we keep them stay
281 * the same as decoder.
282 */
287 if ((ret = str_to_dict(optstr, &opts)) < 0) {
288 fprintf(stderr, "Failed to set encoding parameter.\n");
289 goto fail;
290 }
291 /* There is no "framerate" option in commom option list. Use "-r" to
292 * set framerate, which is compatible with ffmpeg commandline. The
293 * video is assumed to be average frame rate, so set time_base to
294 * 1/framerate. */
295 e = av_dict_get(opts, "r", NULL, 0);
296 if (e) {
297 encoder_ctx->framerate = av_d2q(atof(e->value), INT_MAX);
299 }
300 if ((ret = avcodec_open2(encoder_ctx, enc_codec, &opts)) < 0) {
301 fprintf(stderr, "Failed to open encode codec. Error code: %s\n",
302 av_err2str(ret));
303 av_dict_free(&opts);
304 goto fail;
305 }
306 av_dict_free(&opts);
307
308 if (!(ost = avformat_new_stream(ofmt_ctx, enc_codec))) {
309 fprintf(stderr, "Failed to allocate stream for output format.\n");
310 ret = AVERROR(ENOMEM);
311 goto fail;
312 }
313
316 if (ret < 0) {
317 fprintf(stderr, "Failed to copy the stream parameters. "
318 "Error code: %s\n", av_err2str(ret));
319 goto fail;
320 }
321
322 /* write the stream header */
323 if ((ret = avformat_write_header(ofmt_ctx, NULL)) < 0) {
324 fprintf(stderr, "Error while writing stream header. "
325 "Error code: %s\n", av_err2str(ret));
326 goto fail;
327 }
328 }
331 if ((ret = encode_write(pkt, frame)) < 0)
332 fprintf(stderr, "Error during encoding and writing.\n");
333
334fail:
336 }
337 return ret;
338}
339
340int main(int argc, char **argv)
341{
342 const AVCodec *enc_codec;
343 int ret = 0;
344 AVPacket *dec_pkt = NULL;
345
346 if (argc < 5 || (argc - 5) % 2) {
347 av_log(NULL, AV_LOG_ERROR, "Usage: %s <input file> <encoder> <output file>"
348 " <\"encoding option set 0\"> [<frame_number> <\"encoding options set 1\">]...\n", argv[0]);
349 return 1;
350 }
351 setting_number = (argc - 5) / 2;
354 for (int i = 0; i < setting_number; i++) {
355 dynamic_setting[i].frame_number = atoi(argv[i*2 + 5]);
356 dynamic_setting[i].optstr = argv[i*2 + 6];
357 }
358
360 if (ret < 0) {
361 fprintf(stderr, "Failed to create a QSV device. Error code: %s\n", av_err2str(ret));
362 goto end;
363 }
364
365 dec_pkt = av_packet_alloc();
366 if (!dec_pkt) {
367 fprintf(stderr, "Failed to allocate decode packet\n");
368 goto end;
369 }
370
371 if ((ret = open_input_file(argv[1])) < 0)
372 goto end;
373
374 if (!(enc_codec = avcodec_find_encoder_by_name(argv[2]))) {
375 fprintf(stderr, "Could not find encoder '%s'\n", argv[2]);
376 ret = -1;
377 goto end;
378 }
379
380 if ((ret = (avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, argv[3]))) < 0) {
381 fprintf(stderr, "Failed to deduce output format from file extension. Error code: "
382 "%s\n", av_err2str(ret));
383 goto end;
384 }
385
386 if (!(encoder_ctx = avcodec_alloc_context3(enc_codec))) {
387 ret = AVERROR(ENOMEM);
388 goto end;
389 }
390
391 ret = avio_open(&ofmt_ctx->pb, argv[3], AVIO_FLAG_WRITE);
392 if (ret < 0) {
393 fprintf(stderr, "Cannot open output file. "
394 "Error code: %s\n", av_err2str(ret));
395 goto end;
396 }
397
398 /* read all packets and only transcoding video */
399 while (ret >= 0) {
400 if ((ret = av_read_frame(ifmt_ctx, dec_pkt)) < 0)
401 break;
402
403 if (video_stream == dec_pkt->stream_index)
404 ret = dec_enc(dec_pkt, enc_codec, argv[4]);
405
406 av_packet_unref(dec_pkt);
407 }
408
409 /* flush decoder */
410 av_packet_unref(dec_pkt);
411 if ((ret = dec_enc(dec_pkt, enc_codec, argv[4])) < 0) {
412 fprintf(stderr, "Failed to flush decoder %s\n", av_err2str(ret));
413 goto end;
414 }
415
416 /* flush encoder */
417 if ((ret = encode_write(dec_pkt, NULL)) < 0) {
418 fprintf(stderr, "Failed to flush encoder %s\n", av_err2str(ret));
419 goto end;
420 }
421
422 /* write the trailer for output stream */
423 if ((ret = av_write_trailer(ofmt_ctx)) < 0)
424 fprintf(stderr, "Failed to write trailer %s\n", av_err2str(ret));
425
426end:
432 av_packet_free(&dec_pkt);
434 return ret;
435}
Libavcodec external API header.
Main libavformat public API header.
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:618
int main(int argc, char *argv[])
static int open_input_file(const char *filename)
static AVPacket * pkt
static AVStream * video_stream
static AVFrame * frame
int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
Initialize the AVCodecContext to use the given AVCodec.
AVCodecContext * avcodec_alloc_context3(const AVCodec *codec)
Allocate an AVCodecContext and set its fields to default values.
int avcodec_parameters_from_context(struct AVCodecParameters *par, const AVCodecContext *codec)
Fill the parameters struct based on the values from the supplied codec context.
int avcodec_parameters_to_context(AVCodecContext *codec, const struct AVCodecParameters *par)
Fill the codec context based on the values from the supplied codec parameters.
const AVCodec * avcodec_find_decoder_by_name(const char *name)
Find a registered decoder with the specified name.
const AVCodec * avcodec_find_encoder_by_name(const char *name)
Find a registered encoder with the specified name.
void avcodec_free_context(AVCodecContext **avctx)
Free the codec context and everything associated with it and write NULL to the provided pointer.
@ AV_CODEC_ID_H264
Definition codec_id.h:79
@ AV_CODEC_ID_AV1
Definition codec_id.h:280
@ AV_CODEC_ID_VP8
Definition codec_id.h:192
@ AV_CODEC_ID_HEVC
Definition codec_id.h:226
@ AV_CODEC_ID_MJPEG
Definition codec_id.h:59
@ AV_CODEC_ID_VP9
Definition codec_id.h:220
@ AV_CODEC_ID_MPEG2VIDEO
preferred ID for MPEG-1/2 video decoding
Definition codec_id.h:54
int avcodec_receive_frame(AVCodecContext *avctx, AVFrame *frame)
Return decoded output data from a decoder or encoder (when the AV_CODEC_FLAG_RECON_FRAME flag is used...
int avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt)
Supply raw packet data as input to a decoder.
int avcodec_receive_packet(AVCodecContext *avctx, AVPacket *avpkt)
Read encoded data from the encoder.
int avcodec_send_frame(AVCodecContext *avctx, const AVFrame *frame)
Supply a raw video or audio frame to the encoder.
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 struct AVCodec *c)
Add a new stream to a media file.
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
int av_find_best_stream(AVFormatContext *ic, enum AVMediaType type, int wanted_stream_nb, int related_stream, const struct AVCodec **decoder_ret, int flags)
Find the "best" stream in the file.
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.
AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, struct AVFrame *frame)
Guess the frame rate, based on both the container and codec information.
void av_buffer_unref(AVBufferRef **buf)
Free a given reference and automatically free the buffer if there are no more references to it.
AVBufferRef * av_buffer_ref(const AVBufferRef *buf)
Create a new reference to an AVBuffer.
void av_dict_free(AVDictionary **m)
Free all the memory allocated for an AVDictionary struct and all keys and values.
struct AVDictionary AVDictionary
Definition dict.h:94
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
#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_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition log.h:180
void av_log(void *avcl, int level, const char *fmt,...) av_printf_format(3
Send the specified message to the log if the level is less than or equal to the current av_log_level.
AVRational av_d2q(double d, int max) av_const
Convert a double precision floating point number to a rational.
static av_always_inline AVRational av_inv_q(AVRational q)
Invert a rational.
Definition rational.h:159
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const
Rescale a 64-bit integer by 2 rational numbers.
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_malloc(size_t size) av_malloc_attrib
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
@ AVMEDIA_TYPE_VIDEO
Definition avutil.h:201
int av_opt_set_dict(void *obj, struct AVDictionary **options)
Set all the options from a given dictionary on an object.
static AVBufferRef * hw_device_ctx
Definition hw_decode.c:44
int av_hwdevice_ctx_create(AVBufferRef **device_ctx, enum AVHWDeviceType type, const char *device, AVDictionary *opts, int flags)
Open a device of the specified type and create an AVHWDeviceContext for it.
@ AV_HWDEVICE_TYPE_QSV
Definition hwcontext.h:33
AVOptions.
AVPixelFormat
Pixel format.
Definition pixfmt.h:71
@ AV_PIX_FMT_NONE
Definition pixfmt.h:72
@ AV_PIX_FMT_QSV
HW acceleration through QSV, data[3] contains a pointer to the mfxFrameSurface1 structure.
Definition pixfmt.h:247
static int get_format(AVCodecContext *avctx, const enum AVPixelFormat *pix_fmts)
Definition qsv_decode.c:44
static DynamicSetting * dynamic_setting
static int current_setting_number
static int str_to_dict(char *optstr, AVDictionary **opt)
static int dynamic_set_parameter(AVCodecContext *avctx)
static int setting_number
A reference to a data buffer.
Definition buffer.h:82
main external API structure.
Definition avcodec.h:445
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition avcodec.h:657
int width
picture width / height.
Definition avcodec.h:618
AVRational pkt_timebase
Timebase in which pkt_dts/pts and AVPacket.dts/pts are expressed.
Definition avcodec.h:551
enum AVPixelFormat(* get_format)(struct AVCodecContext *s, const enum AVPixelFormat *fmt)
Callback to negotiate the pixel format.
Definition avcodec.h:787
AVBufferRef * hw_frames_ctx
A reference to the AVHWFramesContext describing the input (for encoding) or output (decoding) frames.
Definition avcodec.h:1475
AVRational framerate
Definition avcodec.h:560
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition avcodec.h:544
AVBufferRef * hw_device_ctx
A reference to the AVHWDeviceContext describing the device which will be used by a hardware encoder/d...
Definition avcodec.h:1497
void * priv_data
Definition avcodec.h:472
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition codec_par.h:55
AVCodec.
Definition codec.h:187
char * value
Definition dict.h:91
Format I/O context.
Definition avformat.h:1255
AVIOContext * pb
I/O context.
Definition avformat.h:1297
AVStream ** streams
A list of all streams in the file.
Definition avformat.h:1323
This structure describes decoded (raw) audio or video data.
Definition frame.h:344
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition frame.h:456
This structure stores compressed data.
Definition packet.h:499
int stream_index
Definition packet.h:524
Stream structure.
Definition avformat.h:743
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition avformat.h:766
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition avformat.h:782
static AVFormatContext * ifmt_ctx
Definition transcode.c:41
static AVFormatContext * ofmt_ctx
Definition transcode.c:42
static int encode_write(AVCodecContext *avctx, AVFrame *frame, FILE *fout)
static AVStream * ost
static AVCodecContext * encoder_ctx
static AVCodecContext * decoder_ctx
static int dec_enc(AVPacket *pkt, const AVCodec *enc_codec)