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Médias (1)
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La conservation du net art au musée. Les stratégies à l’œuvre
26 mai 2011
Mis à jour : Juillet 2013
Langue : français
Type : Texte
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Sur d’autres sites (6775)
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Encoding using ffmpeg library fails
29 septembre 2012, par Erik SwanssonI've spent some time looking at the ffmpeg library and setting things up, I'm opening a .flv file. Reading and decoding and the frames, now I'm trying to encode it to MP4 but my packets end up empty.
My code as follows
int main (){
avformat_open_input(&pFC, "c://wav//test2.flv", NULL, NULL);
po = av_find_stream_info(pFC);
//ADD LOGIC TO FIND VIDEO STREAM
pCodecC = pFC->streams[0]->codec;
decoder = avcodec_find_decoder(pCodecC->codec_id);
encoder = avcodec_find_encoder(pCodecC->codec_id);
po = avcodec_open(pCodecC, decoder);
pCodecE = avcodec_alloc_context3(encoder);
/* put sample parameters */
pCodecE->bit_rate = 400000;
/* resolution must be a multiple of two */
pCodecE->width = 352;
pCodecE->height = 288;
/* frames per second */
pCodecE->time_base.den = 25;
pCodecE->time_base.num = 1;
pCodecE->gop_size = 10; /* emit one intra frame every ten frames */
pCodecE->max_b_frames=1;
pCodecE->pix_fmt = PIX_FMT_YUV420P;
if(pCodecC->codec_id == CODEC_ID_H264)
av_opt_set(pCodecE->priv_data, "preset", "slow", 0);
po = avcodec_open2(pCodecE, encoder, NULL);
AVFrame *pFrame;
// Allocate an AVFrame structure
// Allocate video frame
pFrame=avcodec_alloc_frame();
int frameFinished = 0;
int frame = 0;
int gotpacket = 0;
while(av_read_frame(pFC, &packet) >= 0)
{
if(packet.stream_index==0) //the video stream is 0
{
int len = avcodec_decode_video2(pCodecC, pFrame, &frameFinished, &packet);
if(frameFinished)
{
printf("frame # %i", frame);
po =avcodec_encode_video2(pCodecE, &spacket, pFrame, &gotpacket);
if(gotpacket)
{
printf("packet recieved");
}
frame++;
}
}
av_free_packet(&packet);
}
printf("encoding done");
return 0;
}Basically everything works up to
po =avcodec_encode_video2(pCodecE, &spacket, pFrame, &gotpacket);
Where
&gotpacket
returns 0, as in an empty frame.Not sure what I'm doing wrong.
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How to encode using the FFMpeg in Android (using H263)
3 juillet 2012, par Kenny910I am trying to follow the sample code on encoding in the ffmpeg document and successfully build a application to encode and generate a mp4 file but I face the following problems :
1) I am using the H263 for encoding but I can only set the width and height of the AVCodecContext to 176x144, for other case (like 720x480 or 640x480) it will return fail.
2) I can't play the output mp4 file by using the default Android player, isn't it support H263 mp4 file ? p.s. I can play it by using other player
3) Is there any sample code on encoding other video frame to make a new video (which mean decode the video and encode it back in different quality setting, also i would like to modify the frame content) ?
Here is my code, thanks !
JNIEXPORT jint JNICALL Java_com_ffmpeg_encoder_FFEncoder_nativeEncoder(JNIEnv* env, jobject thiz, jstring filename){
LOGI("nativeEncoder()");
avcodec_register_all();
avcodec_init();
av_register_all();
AVCodec *codec;
AVCodecContext *codecCtx;
int i;
int out_size;
int size;
int x;
int y;
int output_buffer_size;
FILE *file;
AVFrame *picture;
uint8_t *output_buffer;
uint8_t *picture_buffer;
/* Manual Variables */
int l;
int fps = 30;
int videoLength = 5;
/* find the H263 video encoder */
codec = avcodec_find_encoder(CODEC_ID_H263);
if (!codec) {
LOGI("avcodec_find_encoder() run fail.");
}
codecCtx = avcodec_alloc_context();
picture = avcodec_alloc_frame();
/* put sample parameters */
codecCtx->bit_rate = 400000;
/* resolution must be a multiple of two */
codecCtx->width = 176;
codecCtx->height = 144;
/* frames per second */
codecCtx->time_base = (AVRational){1,fps};
codecCtx->pix_fmt = PIX_FMT_YUV420P;
codecCtx->codec_id = CODEC_ID_H263;
codecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
/* open it */
if (avcodec_open(codecCtx, codec) < 0) {
LOGI("avcodec_open() run fail.");
}
const char* mfileName = (*env)->GetStringUTFChars(env, filename, 0);
file = fopen(mfileName, "wb");
if (!file) {
LOGI("fopen() run fail.");
}
(*env)->ReleaseStringUTFChars(env, filename, mfileName);
/* alloc image and output buffer */
output_buffer_size = 100000;
output_buffer = malloc(output_buffer_size);
size = codecCtx->width * codecCtx->height;
picture_buffer = malloc((size * 3) / 2); /* size for YUV 420 */
picture->data[0] = picture_buffer;
picture->data[1] = picture->data[0] + size;
picture->data[2] = picture->data[1] + size / 4;
picture->linesize[0] = codecCtx->width;
picture->linesize[1] = codecCtx->width / 2;
picture->linesize[2] = codecCtx->width / 2;
for(l=0;l/encode 1 second of video
for(i=0;i/prepare a dummy image YCbCr
//Y
for(y=0;yheight;y++) {
for(x=0;xwidth;x++) {
picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
}
}
//Cb and Cr
for(y=0;yheight/2;y++) {
for(x=0;xwidth/2;x++) {
picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
}
}
//encode the image
out_size = avcodec_encode_video(codecCtx, output_buffer, output_buffer_size, picture);
fwrite(output_buffer, 1, out_size, file);
}
//get the delayed frames
for(; out_size; i++) {
out_size = avcodec_encode_video(codecCtx, output_buffer, output_buffer_size, NULL);
fwrite(output_buffer, 1, out_size, file);
}
}
//add sequence end code to have a real mpeg file
output_buffer[0] = 0x00;
output_buffer[1] = 0x00;
output_buffer[2] = 0x01;
output_buffer[3] = 0xb7;
fwrite(output_buffer, 1, 4, file);
fclose(file);
free(picture_buffer);
free(output_buffer);
avcodec_close(codecCtx);
av_free(codecCtx);
av_free(picture);
LOGI("finish");
return 0; } -
iPhone camera shooting video using the AVCaptureSession and using ffmpeg CMSampleBufferRef a change in h.264 format is the issue. please advice
4 janvier 2012, par isaiahMy goal is h.264/AAC , mpeg2-ts streaming to server from iphone device.
Current my source is FFmpeg+libx264 compile success. I Know gnu License. I want the demo program.
I'm want to know that
1.CMSampleBufferRef to AVPicture data is success ?
avpicture_fill((AVPicture*)pFrame, rawPixelBase, PIX_FMT_RGB32, width, height);
pFrame linesize and data is not null but pst -9233123123 . outpic also .
Because of this I have to guess 'non-strictly-monotonic PTS' message2.This log is repeat.
encoding frame (size= 0)
encoding frame = "" , 'avcodec_encode_video' return 0 is success but always 0 .I don't know what to do...
2011-06-01 15:15:14.199 AVCam[1993:7303] pFrame = avcodec_alloc_frame();
2011-06-01 15:15:14.207 AVCam[1993:7303] avpicture_fill = 1228800
Video encoding
2011-0601 15:5:14.215 AVCam[1993:7303] codec = 5841844
[libx264 @ 0x1441e00] using cpu capabilities: ARMv6 NEON
[libx264 @ 0x1441e00] profile Constrained Baseline, level 2.0[libx264 @ 0x1441e00] non-strictly-monotonic PTS
encoding frame (size= 0)
encoding frame
[libx264 @ 0x1441e00] final ratefactor: 26.743.I have to guess 'non-strictly-monotonic PTS' message is the cause of all problems.
what is this 'non-strictly-monotonic PTS' .this is source
(void) captureOutput:(AVCaptureOutput *)captureOutput
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
fromConnection:(AVCaptureConnection *)connection
{
if( !CMSampleBufferDataIsReady(sampleBuffer) )
{
NSLog( @"sample buffer is not ready. Skipping sample" );
return;
}
if( [isRecordingNow isEqualToString:@"YES"] )
{
lastSampleTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
if( videoWriter.status != AVAssetWriterStatusWriting )
{
[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:lastSampleTime];
}
if( captureOutput == videooutput )
{
[self newVideoSample:sampleBuffer];
CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(pixelBuffer, 0);
// access the data
int width = CVPixelBufferGetWidth(pixelBuffer);
int height = CVPixelBufferGetHeight(pixelBuffer);
unsigned char *rawPixelBase = (unsigned char *)CVPixelBufferGetBaseAddress(pixelBuffer);
AVFrame *pFrame;
pFrame = avcodec_alloc_frame();
pFrame->quality = 0;
NSLog(@"pFrame = avcodec_alloc_frame(); ");
// int bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0);
// int bytesSize = height * bytesPerRow ;
// unsigned char *pixel = (unsigned char*)malloc(bytesSize);
// unsigned char *rowBase = CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
// memcpy (pixel, rowBase, bytesSize);
int avpicture_fillNum = avpicture_fill((AVPicture*)pFrame, rawPixelBase, PIX_FMT_RGB32, width, height);//PIX_FMT_RGB32//PIX_FMT_RGB8
//NSLog(@"rawPixelBase = %i , rawPixelBase -s = %s",rawPixelBase, rawPixelBase);
NSLog(@"avpicture_fill = %i",avpicture_fillNum);
//NSLog(@"width = %i,height = %i",width, height);
// Do something with the raw pixels here
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
//avcodec_init();
//avdevice_register_all();
av_register_all();
AVCodec *codec;
AVCodecContext *c= NULL;
int out_size, size, outbuf_size;
//FILE *f;
uint8_t *outbuf;
printf("Video encoding\n");
/* find the mpeg video encoder */
codec =avcodec_find_encoder(CODEC_ID_H264);//avcodec_find_encoder_by_name("libx264"); //avcodec_find_encoder(CODEC_ID_H264);//CODEC_ID_H264);
NSLog(@"codec = %i",codec);
if (!codec) {
fprintf(stderr, "codec not found\n");
exit(1);
}
c= avcodec_alloc_context();
/* put sample parameters */
c->bit_rate = 400000;
c->bit_rate_tolerance = 10;
c->me_method = 2;
/* resolution must be a multiple of two */
c->width = 352;//width;//352;
c->height = 288;//height;//288;
/* frames per second */
c->time_base= (AVRational){1,25};
c->gop_size = 10;//25; /* emit one intra frame every ten frames */
//c->max_b_frames=1;
c->pix_fmt = PIX_FMT_YUV420P;
c ->me_range = 16;
c ->max_qdiff = 4;
c ->qmin = 10;
c ->qmax = 51;
c ->qcompress = 0.6f;
/* open it */
if (avcodec_open(c, codec) < 0) {
fprintf(stderr, "could not open codec\n");
exit(1);
}
/* alloc image and output buffer */
outbuf_size = 100000;
outbuf = malloc(outbuf_size);
size = c->width * c->height;
AVFrame* outpic = avcodec_alloc_frame();
int nbytes = avpicture_get_size(PIX_FMT_YUV420P, c->width, c->height);
//create buffer for the output image
uint8_t* outbuffer = (uint8_t*)av_malloc(nbytes);
#pragma mark -
fflush(stdout);
<pre>// int numBytes = avpicture_get_size(PIX_FMT_YUV420P, c->width, c->height);
// uint8_t *buffer = (uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
//
// //UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:@"10%d", i]];
// CGImageRef newCgImage = [self imageFromSampleBuffer:sampleBuffer];//[image CGImage];
//
// CGDataProviderRef dataProvider = CGImageGetDataProvider(newCgImage);
// CFDataRef bitmapData = CGDataProviderCopyData(dataProvider);
// buffer = (uint8_t *)CFDataGetBytePtr(bitmapData);
//
// avpicture_fill((AVPicture*)pFrame, buffer, PIX_FMT_RGB8, c->width, c->height);
avpicture_fill((AVPicture*)outpic, outbuffer, PIX_FMT_YUV420P, c->width, c->height);
struct SwsContext* fooContext = sws_getContext(c->width, c->height,
PIX_FMT_RGB8,
c->width, c->height,
PIX_FMT_YUV420P,
SWS_FAST_BILINEAR, NULL, NULL, NULL);
//perform the conversion
sws_scale(fooContext, pFrame->data, pFrame->linesize, 0, c->height, outpic->data, outpic->linesize);
// Here is where I try to convert to YUV
/* encode the image */
out_size = avcodec_encode_video(c, outbuf, outbuf_size, outpic);
printf("encoding frame (size=%5d)\n", out_size);
printf("encoding frame %s\n", outbuf);
//fwrite(outbuf, 1, out_size, f);
// free(buffer);
// buffer = NULL;
/* add sequence end code to have a real mpeg file */
// outbuf[0] = 0x00;
// outbuf[1] = 0x00;
// outbuf[2] = 0x01;
// outbuf[3] = 0xb7;
//fwrite(outbuf, 1, 4, f);
//fclose(f);
free(outbuf);
avcodec_close(c);
av_free(c);
av_free(pFrame);
printf("\n");
</pre>