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• FFmpeg does not decode h264 stream

  5 juillet 2012, par HAPPY_TIGER

  I am trying to decode h264 stream from rtsp server and render it on iPhone.

  I found some libraries and read some articles about it.

  Libraries are from dropCam for iPhone called RTSPClient and DecoderWrapper.

  But I can not decode frame data with DecodeWrapper that using on ffmpeg.

  Here are my code.

  VideoViewer.m
  
  
  
  - (void)didReceiveFrame:(NSData*)frameData presentationTime:(NSDate*)presentationTime
  
  {
  
      [VideoDecoder staticInitialize];
  
      mConverter = [[VideoDecoder alloc] initWithCodec:kVCT_H264 colorSpace:kVCS_RGBA32 width:320 height:240 privateData:nil];
  
  
  
  
  
      [mConverter decodeFrame:frameData];
  
  
  
      if ([mConverter isFrameReady]) {
  
          UIImage *imageData =[mConverter getDecodedFrame];
  
          if (imageData) {
  
              [mVideoView setImage:imageData];
  
              NSLog(@"decoded!");
  
          }
  
      }
  
  }
  
  
  
  ---VideoDecoder.m---
  
  - (id)initWithCodec:(enum VideoCodecType)codecType 
  
           colorSpace:(enum VideoColorSpace)colorSpace 
  
                width:(int)width 
  
               height:(int)height 
  
          privateData:(NSData*)privateData {
  
      if(self = [super init]) {
  
  
  
          codec = avcodec_find_decoder(CODEC_ID_H264);
  
          codecCtx = avcodec_alloc_context();
  
  
  
          // Note: for H.264 RTSP streams, the width and height are usually not specified (width and height are 0).  
  
          // These fields will become filled in once the first frame is decoded and the SPS is processed.
  
          codecCtx->width = width;
  
          codecCtx->height = height;
  
  
  
          codecCtx->extradata = av_malloc([privateData length]);
  
          codecCtx->extradata_size = [privateData length];
  
          [privateData getBytes:codecCtx->extradata length:codecCtx->extradata_size];
  
          codecCtx->pix_fmt = PIX_FMT_RGBA;
  
  #ifdef SHOW_DEBUG_MV
  
          codecCtx->debug_mv = 0xFF;
  
  #endif
  
  
  
          srcFrame = avcodec_alloc_frame();
  
          dstFrame = avcodec_alloc_frame();
  
  
  
          int res = avcodec_open(codecCtx, codec);
  
          if (res < 0)
  
          {
  
              NSLog(@"Failed to initialize decoder");
  
          }
  
  
  
      }
  
  
  
      return self;    
  
  }
  
  
  
  - (void)decodeFrame:(NSData*)frameData {
  
  
  
  
  
      AVPacket packet = {0};
  
      packet.data = (uint8_t*)[frameData bytes];
  
      packet.size = [frameData length];
  
  
  
      int frameFinished=0;
  
      NSLog(@"Packet size===>%d",packet.size);
  
      // Is this a packet from the video stream?
  
      if(packet.stream_index==0)
  
      {
  
          int res = avcodec_decode_video2(codecCtx, srcFrame, &frameFinished, &packet);
  
          NSLog(@"Res value===>%d",res);
  
          NSLog(@"frame data===>%d",(int)srcFrame->data);
  
          if (res < 0)
  
          {
  
              NSLog(@"Failed to decode frame");
  
          }
  
      }
  
      else 
  
      {
  
          NSLog(@"No video stream found");
  
      }
  
  
  
  
  
      // Need to delay initializing the output buffers because we don't know the dimensions until we decode the first frame.
  
      if (!outputInit) {
  
          if (codecCtx->width > 0 && codecCtx->height > 0) {
  
  #ifdef _DEBUG
  
              NSLog(@"Initializing decoder with frame size of: %dx%d", codecCtx->width, codecCtx->height);
  
  #endif
  
  
  
              outputBufLen = avpicture_get_size(PIX_FMT_RGBA, codecCtx->width, codecCtx->height);
  
              outputBuf = av_malloc(outputBufLen);
  
  
  
              avpicture_fill((AVPicture*)dstFrame, outputBuf, PIX_FMT_RGBA, codecCtx->width, codecCtx->height);
  
  
  
              convertCtx = sws_getContext(codecCtx->width, codecCtx->height, codecCtx->pix_fmt,  codecCtx->width, 
  
                                          codecCtx->height, PIX_FMT_RGBA, SWS_FAST_BILINEAR, NULL, NULL, NULL); 
  
  
  
              outputInit = YES;
  
              frameFinished=1;
  
          }
  
          else {
  
              NSLog(@"Could not get video output dimensions");
  
          }
  
      }
  
  
  
      if (frameFinished)
  
          frameReady = YES;
  
  
  
  }

  The console shows me as follows.

  2011-05-16 20:16:04.223 RTSPTest1[41226:207] Packet size===>359
  
  [h264 @ 0x5815c00] no frame!
  
  2011-05-16 20:16:04.223 RTSPTest1[41226:207] Res value===>-1
  
  2011-05-16 20:16:04.224 RTSPTest1[41226:207] frame data===>101791200
  
  2011-05-16 20:16:04.224 RTSPTest1[41226:207] Failed to decode frame
  
  2011-05-16 20:16:04.225 RTSPTest1[41226:207] decoded!
  
  2011-05-16 20:16:04.226 RTSPTest1[41226:207] Packet size===>424
  
  [h264 @ 0x5017c00] no frame!
  
  2011-05-16 20:16:04.226 RTSPTest1[41226:207] Res value===>-1
  
  2011-05-16 20:16:04.227 RTSPTest1[41226:207] frame data===>81002704
  
  2011-05-16 20:16:04.227 RTSPTest1[41226:207] Failed to decode frame
  
  2011-05-16 20:16:04.228 RTSPTest1[41226:207] decoded!
  
  2011-05-16 20:16:04.229 RTSPTest1[41226:207] Packet size===>424
  
  [h264 @ 0x581d000] no frame!
  
  2011-05-16 20:16:04.229 RTSPTest1[41226:207] Res value===>-1
  
  2011-05-16 20:16:04.230 RTSPTest1[41226:207] frame data===>101791616
  
  2011-05-16 20:16:04.230 RTSPTest1[41226:207] Failed to decode frame
  
  2011-05-16 20:16:04.231 RTSPTest1[41226:207] decoded!
  
  . . . .  .

  But the simulator shows nothing.

  What's wrong with my code.

  Help me solve this problem.

  Thanks for your answers.

• Does 'keyint infinite' improve overall compression with crf and mb-tree ?

  23 avril 2012, par HitomiTenshi

  After reading what intra-refresh does, I kinda got confused. I'm encoding for YouTube and YouTube will re-encode the video-file anyways, so I thought "why not removing all these heavy IDR-frames ?" I just want to compress my video as hard as possible, enabling everything that could help me getting a lower filesize, but still maintaining a high quality.

  I used to test around stuff with lossless QP encoding, but the only thing I could max out was the merange. Here is a paste of my x264 settings : Pastebin.

  I want to achieve highest compression while maintaining visually lossless quality. (using crf values around 10 - 13, and merange 32)

  Could anyone give me advice on how to compress my video super hard (without touching the crf value !). I also want to know if it's true, that keyint infinite reduces overall compression.

• FFmpeg mp4 videos load very slow outside of network

  6 juin 2014, par user3550401

  I used ffmpeg to convert my videos to mp4 using libx264 and qt fast start. Im playing my videos through the HTML tag, and when im inside my network where my website is, everything plays fast. But when i try to play the video from an outside network, I have to wait about 10 seconds before a 5 second video is played. And even when its playing, its super choppy. Any reason on why this is ? I am playing the videos in Safari on my iPhone.

  Here is how im encoding my videos :

  ffmpeg -i video.ts -i css/watermark.png -filter_complex overlay=10:main_h-overlay_h-10 -shortest -b:v 800k -vcodec libx264 -acodec libfaac -ar 44100 -ac 2 -b:a 128k -movflags faststart -map_metadata -1 video.mp4