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• Resize video using FFmpeg C API

  28 février 2012, par cr_az

  I am trying to resize video file on Android device using FFmpeg. Remark : I cant use FFmpeg as binary - in my case it should be used as shared library (only FFmpeg C API is accessible).

  I did not find any documentation regarding video resizing, however it looks like algorithm is following :

  10 OPEN video_stream FROM video.mp4
  
  20 READ packet FROM video_stream INTO frame
  
  30 IF frame NOT COMPLETE GOTO 20
  
  40 RESIZE frame
  
  50 WRITE frame TO converted_video.mp4
  
  60 GOTO 20

  Should I use sws_scale function in order to resize frame ? Is there any other (easier ?) way to resize video file using FFmpeg C API ?

• streaming camera captured video to another location

  28 février 2012, par Fei Su

  I am using Kinect camera capture images and compress them to video and save the video into the disk(python opencv). How can I stream and display it at another location ? Because the video is made at real-time and I also need to display and stream it in real time.

• 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 isaiah

  My 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' message 

  2.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: 26.74

  3.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>