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• avcodec/vdpau : Support for VDPAU accelerated HEVC decoding

  13 juin 2015, par Philip Langdale

  avcodec/vdpau : Support for VDPAU accelerated HEVC decoding
  This change introduces basic support for HEVC decoding through vdpau.
  
  Right now, there are problems with the nvidia driver/library implementation
  
  that mean that frames are incorrectly laid out in memory when they are
  
  returned from the decoder, and it is normally impossible to recover the
  
  complete decoded frame due to loss of data from alignment inconsistencies.
  I obviously hope that nvidia will be fixing it in due course - I’ve verified
  
  the problems exist with their example application.
  As such, this support is not useful for any real world application, but I
  
  believe that it is correct (with the caveat that the mangled frames may hide
  
  problems) and will work properly once the nvidia problem is fixed.
  Right now it appears that any file encoded by x265 or nvenc is decoded
  
  correctly, but that’s because these files don’t use a bunch of HEVC
  
  features.
  Quick summary :
  Features that seem to work :
  1) Short Term References
  
  2) Scaling Lists
  
  3) Tiling
  Features with known problems :
  1) Long Term References
  It’s hard to tell what’s going on here. After I read the nvidia example
  
  app that does not set the IsLongTerm flag on LTRs, and changed my code,
  
  a bunch of frames using LTR started to display correctly, but there
  
  are still samples with glitches that are related to LTRs.
  In terms of real world files, both x265 and nvenc only use short term
  
  refs from this list. The divx encoder seems similar.
  Signed-off-by : Philip Langdale <philipl@overt.org>
  

  • [DH] configure
  • [DH] libavcodec/Makefile
  • [DH] libavcodec/allcodecs.c
  • [DH] libavcodec/hevc.c
  • [DH] libavcodec/vdpau_hevc.c
  • [DH] libavcodec/vdpau_internal.h

• Creating screenshot/image from Twitch stream

  22 juillet 2015, par danL

  I’ve messed around with FFmpeg some time ago and remember using it to fetch preview images for video files. My question is, is this the correct path to be going down for the purpose of getting images from a Twitch live stream ? What I need to do is get a screenshot of the end of a Twitch stream (the final scoreboard in a video game) and save that screen shot.

  I’m pretty sure I could get the code written, but I want to make sure there isn’t a better way of accomplishing this task because it seems like it would have gotten easier over the years. If there are any other libraries/APIs that would be more efficient than executing FFMpeg all the time.

  I hope there’s been some improvement in PHP video handling, but I’ve searched around and can’t find anything.

• How to stream a usb webcam to an android phone with ffmpeg and ffserver ?

  26 juillet 2015, par victor jung

  I am desperately trying to live stream the usb webcam from a linux computer to my android phone.
  I tried with ffmpeg and ffserver, to create the stream and with videoview in android to display it. I tried all the possible format/encoder/protocols possibilities but nothing worked. In most case I am able to open the stream in VLC in another PC, but I was never able to play on my phone. I always get this error :
  "can’t play this video"
  Here is my app code :

  package com.example.victor.videostream;
  
  import android.os.Bundle;
  
  import android.app.Activity;
  
  import android.view.View;
  
  import android.net.Uri;
  
  import android.widget.MediaController;
  
  import android.widget.VideoView;
  
  public class MainActivity extends Activity
  
   {
  
  VideoView videoView;
  
  @Override
  
   protected void onCreate(Bundle savedInstanceState)
  
  {
  
       super.onCreate(savedInstanceState);
  
       videoView = null;
  
       setContentView(R.layout.activity_main);
  
  
  
       videoView =(VideoView)findViewById(R.id.VideoView);
  
       MediaController mediaController= new MediaController(this);
  
       mediaController.setAnchorView(videoView);
  
  
  
   Uri uri = Uri.parse("http://host:port/mystream.3gp");
  
    videoView.setMediaController(mediaController);
  
    videoView.setVideoURI(uri);
  
    videoView.requestFocus();
  
    videoView.start();
  
         }
  
          }

  I read here

  about god encoding practice for android, but even with .3gp format encoded with mpeg4 as suggested it doesn’t work. Have any body once succeeded doing this ?
  I am also up to discover other possibilities to stream this webcam to my android if you have any ideas.
  this is the closest post I found but no solution...
  Hope somebody can help !
  thanks for reading.