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• ffmpeg quality with watermark

  17 juin 2012, par trialgod

  i want to add a watermark to a video with ffmpeg. At this time nearly all things are computing properly, except the quality of the new video is massively lower than in the one of the original video.

  I also use ffmpeg-php and tried to set the minrate to the Bitrate of the original, but then i get an Error. Code seems like this at the moment.

  $video     = new ffmpeg_movie('hot_wheels_for_adults.flv');
  
  $watermark = 'path/to/watermark.png';
  
  $width     = $video->getFrameWidth();
  
  $height    = $video->getFrameHeight();
  
  $exec = 'ffmpeg -i hot_wheels_for_adults.flv ' .
  
          '-y -vf "movie=' . $watermark . ' ' .
  
          '[watermark]; [in][watermark] overlay=main_w-overlay_w-10:main_h-overlay_h-10 [out]" ' .
  
          '-f flv -s ' . $width . 'x' . $height . ' ' .
  
          '-minrate ' . $video->getBitRate() . ' ' .
  
          'bla2.flv';

  Thats it. Without the '-minrate' line the quality isnt good.
  Originalrate = 630615,
  Rate of new Video = 328000.

  With the '-sameq' flag i got a good quality, but it is raised from 6,5MB to nearly 30MB...

  What can i do now ?

• video frames render slow using opengl and ffmpeg in iphone

  17 février 2012, par resident_

  I'm developing an video player for iPhone. I'm using ffmpeg libraries to decode frames of video and I'm using opengl 2.0 to render the frames to the screen.

  But my app is very slow render the frames and some videos played slowly.

  I have played AVI, MOV, FLV, MP4 and WMV, and only several AVI files are correct played.

  I don't have much idea of ffmpeg and opengl, and I have used a tutorials and examples until now. But I think that the problem can be two things :

  1. The render method is very slowly. I don't use correctly the glTexSubImage2D function.

  2. I don't scale the frames correctly. I don't use correctly the sws_getContext function.

  I'm here parts of my code, to see if anyone can help me.

  So I use sws_getContext

   ctx->p_sws_ctx = sws_getContext(ctx->p_video_ctx->width, 
  
                                  ctx->p_video_ctx->height, 
  
                                  ctx->p_video_ctx->pix_fmt, 
  
                                  ctx->p_video_ctx->width, 
  
                                  ctx->p_video_ctx->height,
  
                                  PIX_FMT_RGB565, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  
  
  
  
  
  
  
  
  // Framebuffer for RGB data
  
  ctx->p_frame_buffer = malloc(avpicture_get_size(PIX_FMT_RGB565,
  
                                                  ctx->p_video_ctx->width, 
  
                                                  ctx->p_video_ctx->height));
  
  
  
  avpicture_fill((AVPicture*)ctx->p_picture_rgb, ctx->p_frame_buffer, PIX_FMT_RGB565, 
  
                 ctx->p_video_ctx->width, 
  
                 ctx->p_video_ctx->height);

  My render method of opengl 2.0

  - (void) render: (uint8_t*) buffer

  [EAGLContext setCurrentContext:context] ;

  glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);
  
  glViewport(0, 0, backingWidth, backingHeight);
  
  
  
  glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
  
  
  
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
  
  
  // OpenGL loads textures lazily so accessing the buffer is deferred until draw; notify
  
  // the movie player that we're done with the texture after glDrawArrays.          
  
  glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, mFrameW, mFrameH, GL_RGB,GL_UNSIGNED_SHORT_5_6_5, buffer);
  
  
  
  glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
  
  
  
  
  
  [moviePlayerDelegate bufferDone];
  
  
  
  glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
  
  [context presentRenderbuffer:GL_RENDERBUFFER];

  Someone, can I Help me ?

  Thanks,

• Simple example of using ffmpeg as a Python subprocess, and "checking in" on the conversion

  30 août 2012, par ensnare

  I'm looking to convert a large directory of movies from one format to another, and to check in on the status of the conversion. I'm programming in Python.

  Something like this :

  >> m = MovieGenerator()
  
  >> m.convertMovie('/path/to/movie/movie1.avi')
  
  >> print m.status
  
  >> 35 frames completed

  Is this possible (or recommended) ? Does anyone have a working example of how to use ffmpeg as a subprocess ?

  Once the conversion is happening, is there any way to "check in" on the status of the conversion (for example, how many frames have been completed ?)