Recherche avancée

Sur d’autres sites (6919)

• Black screen when playing a video with ffmpeg and SDL on iOS

  1er avril 2012, par patrick

  I'm attempting to create a video player on iOS using ffmpeg and SDL. I'm decoding the video stream and attempting to convert the pixel data into a SDL_Surface and then convert that over to an SDL_Texture and render it on screen. However, all I'm getting is a black screen. I know the video file is good and can be viewed fine from VLC. Any idea what I'm missing here ?

  Initialization code :

      // initialize SDL (Simple DirectMedia Layer) to playback the content
  
      if( SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER) ) 
  
      {
  
          DDLogError(@"Unable to initialize SDL");
  
          return NO; 
  
      }
  
  
  
      // create window and renderer 
  
      window = SDL_CreateWindow(NULL, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT,
  
                                SDL_WINDOW_OPENGL | SDL_WINDOW_BORDERLESS |
  
                                SDL_WINDOW_SHOWN);
  
      if ( window == 0 ) 
  
      {
  
          DDLogError(@"Unable to initialize SDL Window");
  
      }
  
  
  
      renderer = SDL_CreateRenderer(window, -1, 0);
  
      if ( !renderer ) 
  
      {
  
          DDLogError(@"Unable to initialize SDL Renderer");
  
      }
  
  
  
      // Initialize the FFMpeg and register codecs and their respected file formats
  
      av_register_all();

  Playback code :
  AVFormatContext *formatContext = NULL ;

  DDLogInfo(@"Opening media file at location:%@", filePath);
  
  
  
  const char *filename = [filePath cStringUsingEncoding:NSUTF8StringEncoding];
  
  // Open media file
  
  if( avformat_open_input(&formatContext, filename, NULL, NULL) != 0 )
  
  {
  
      DDLogWarn(@"Unable to open media file. [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unable to open file.", @"Media playback failed, unable to open file.");
  
  
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_OPEN 
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Couldn't open file
  
  }
  
  
  
  // Retrieve stream information
  
  if( avformat_find_stream_info(formatContext, NULL) <= 0 )
  
  {
  
      DDLogWarn(@"Unable to locate stream information for file. [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unable to find audio/video stream information.", @"Media playback failed, unable to find stream information.");
  
  
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_FIND_STREAM
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO;  // Missing stream information
  
  }
  
  
  
  // Find the first video or audio stream
  
  int videoStream = -1;
  
  int audioStream = -1;
  
  
  
  DDLogInfo(@"Locating stream information for media file");
  
  
  
  for( int index=0; index<(formatContext->nb_streams); index++)
  
  {
  
      if( formatContext->streams[index]->codec->codec_type==AVMEDIA_TYPE_VIDEO ) 
  
      {
  
          DDLogInfo(@"Found video stream");
  
          videoStream = index;
  
          break;
  
      }
  
      else if( mediaType == AUDIO_FILE && 
  
              (formatContext->streams[index]->codec->codec_type==AVMEDIA_TYPE_AUDIO) )
  
      {
  
          DDLogInfo(@"Found audio stream");
  
          audioStream = index;
  
          break;
  
      }
  
  }
  
  
  
  if( videoStream == -1 && (audioStream == -1) )
  
  {
  
      DDLogWarn(@"Unable to find video or audio stream for file");
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unable to locate audio/video stream.", @"Media playback failed, unable to locate media stream.");
  
  
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_FIND_STREAM
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Didn't find a video or audio stream
  
  }
  
  
  
  // Get a pointer to the codec context for the video/audio stream
  
  AVCodecContext *codecContext;
  
  
  
  DDLogInfo(@"Attempting to locate the codec for the media file");
  
  
  
  if ( videoStream > -1 ) 
  
  {
  
      codecContext = formatContext->streams[videoStream]->codec;
  
  
  
  }
  
  else 
  
  {
  
      codecContext = formatContext->streams[audioStream]->codec;
  
  }
  
  
  
  // Now that we have information about the codec that the file is using,
  
  // we need to actually open the codec to decode the content
  
  
  
  DDLogInfo(@"Attempting to open the codec to playback the media file");
  
  
  
  AVCodec *codec;
  
  
  
  // Find the decoder for the video stream
  
  codec = avcodec_find_decoder(codecContext->codec_id);
  
  if( codec == NULL ) 
  
  {
  
      DDLogWarn(@"Unsupported codec! Cannot playback meda file [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unsupported file format. Cannot playback media.", @"Media playback failed, unsupported codec.");
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNSUPPORTED_CODEC
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Codec not found
  
  }
  
  
  
  // Open codec
  
  if( avcodec_open2(codecContext, codec, NULL) < 0 )
  
  {
  
      DDLogWarn(@"Unable to open codec! Cannot playback meda file [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unable to open media codec. Cannot playback media.", @"Media playback failed, cannot open codec.");
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_LOAD_CODEC
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Could not open codec
  
  }
  
  
  
  // Allocate player frame
  
   AVFrame *playerFrame=avcodec_alloc_frame();
  
  
  
  // Allocate an AVFrame structure
  
  AVFrame *RGBframe=avcodec_alloc_frame();
  
  if( RGBframe==NULL )
  
  {
  
      // could not create a frame to convert our video frame
  
      // to a 16-bit RGB565 frame.
  
  
  
      DDLogWarn(@"Unable to convert video frame. Cannot playback meda file [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Problems interpreting video frame information.", @"Media playback failed, cannot convert frame.");
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_LOAD_FRAME
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Could not open codec
  
  }
  
  
  
  int frameFinished = 0;
  
  AVPacket packet;
  
  
  
  // Figure out the destination width/height based on the screen size
  
  int destHeight = codecContext->height;
  
  int destWidth  = codecContext->width;
  
  if ( destHeight > SCREEN_HEIGHT || (destWidth > SCREEN_WIDTH) ) 
  
  {
  
      if ( destWidth > SCREEN_WIDTH ) 
  
      {
  
          float percentDiff = ( destWidth - SCREEN_WIDTH ) / (float)destWidth;
  
          destWidth  = destWidth  - (int)(destWidth * percentDiff );
  
          destHeight = destHeight - (int)(destHeight * percentDiff );
  
      }
  
  
  
      if ( destHeight > SCREEN_HEIGHT ) 
  
      {
  
          float percentDiff = (destHeight - SCREEN_HEIGHT ) / (float)destHeight;
  
          destWidth  = destWidth  - (int)(destWidth * percentDiff );
  
          destHeight = destHeight - (int)(destHeight * percentDiff );
  
      }
  
  }
  
  
  
  SwsContext *swsContext = sws_getContext(codecContext->width, codecContext->height, codecContext->pix_fmt, destWidth, destHeight, PIX_FMT_RGB565, SWS_BICUBIC, NULL, NULL, NULL);
  
  
  
  while( av_read_frame(formatContext, &packet) >= 0 ) 
  
  {
  
      // Is this a packet from the video stream?
  
      if( packet.stream_index == videoStream ) 
  
      {
  
          // Decode video frame
  
          avcodec_decode_video2(codecContext, playerFrame, &frameFinished, &packet);
  
  
  
          // Did we get a video frame?
  
          if( frameFinished != 0 ) 
  
          {
  
              // Convert the content over to RGB565 (16-bit RGB) to playback with SDL
  
  
  
              uint8_t *dst[3];
  
              int dstStride[3];
  
  
  
              // Set the destination stride
  
              for (int plane = 0; plane < 3; plane++) 
  
              {
  
                  dstStride[plane] = codecContext->width*2;
  
                  dst[plane]= (uint8_t*) malloc(dstStride[plane]*destHeight);
  
              }
  
  
  
              sws_scale(swsContext, playerFrame->data, 
  
                        playerFrame->linesize, 0, 
  
                        destHeight, 
  
                        dst, dstStride);
  
  
  
              // Create the SDL surface frame that we are going to use to draw our video
  
  
  
              // 16-bit RGB so 2 bytes per pixel (pitch = width*(bytes per pixel))
  
              int pitch = destWidth*2;
  
              SDL_Surface *frameSurface = SDL_CreateRGBSurfaceFrom(dst[0], destWidth, destHeight, 16, pitch, 0, 0, 0, 0);
  
  
  
              // Clear the old frame first
  
              SDL_RenderClear(renderer);
  
  
  
              // Move the frame over to a texture and render it on screen
  
              SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer, frameSurface);
  
              SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
  
  
  
              // Draw the new frame on the screen
  
              SDL_RenderPresent(renderer);
  
  
  
              SDL_DestroyTexture(texture);
  
              SDL_FreeSurface(frameSurface);
  
          }

• How to record audio in android ?

  28 mars 2012, par newentry

  I am doing a loopback test in android, which record's audio using AudioRecorder then encode the uncompressed pcm into speex after that i decode speex back to pcm and given to AudioPlayer for playing .Later case i will test between two devices P2P . I am trying to record audio , similar to call recording in which save both sender and receiver voide into a single file mp4 format .Can anybody suggest me a good direction to proceed and also is it possible to achieve this through ffmpeg ported for android ?

  thanks,

• Decode to multiple wavs using ffmpeg ?

  15 mars 2012, par get8p

  Heythere, good man.
  My goal is to decode an ac3 from avi to multiple wavs - each for each channel, using ffmpeg, please, help me with that.

  Now, using

  ffmpeg.exe -i teh.avi -c:a copy teh.ac3 teh.wav

  Would decode it to a sinle wav, and typing teh.wavs won't help...
  I know it can be done with other tools, but I want to know how it's achievable with ffmpeg. Thank in advance.