On 26.04.19 06:12, Phyllis Smith wrote:

    

    

      
      

        

          

            
Pierre:
              just some commentary here.

            

          

          

          

            
I wish it had worked
              better....

            

            
That
                is what I was afraid of. 

            

              

              I did a lot of tests with the same.xml file that contains
              4 mixers. Each 

              time I checked both with mpeg proxies and original DNxHD
              sources.

            

            
When
                I load DNxHD sources, it falls back to using software as
                seen on the startup window:

              

            


              

            

              
 Decoder dnxhd does not
                support device type vdpau.

                HW device init failed, using SW decode.

                file:/root/Downloads/DNx145_1080i_2997.gxf

                  err: Success

              


              

            

            

              
FFmpeg
                apparently can not handle dnxhd with vdpau so that would
                be why you see not speed up for those.

              

              

            

          

        

      

    

    
Here are some background information about hardware acceleration.

      

      Hardware acceleration means that only the most common codecs, such
      as MPEG-2 and MPEG-4, are accelerated. The graphics card
      manufacturers have optimized the GPU to be able to play these
      certain video formats particularly efficiently. Conversely, this
      means that many other formats are not optimized and are played
      back normally unoptimized. These unoptimized formats do not
      provide any speed advantages. In this case, the CPU is normally
      used in the same way as if the hardware acceleration were
      deactivated.

      The hardware acceleration only makes sense if you have a
      relatively strong graphics card. Very old graphics cards or
      non-performing graphics cards will probably bring only little
      speed advantage or no speed advantage at all. 

      

      But if you work for example with MPEG-2, MPEG-4 and H.264/MPEG-4
      AVC encoded video material, you will see a significant speed
      advantage and performance increase. Depending on the graphics
      card, up to ten times higher processing speeds can be achieved.

      

      Nvidia supports VDPAU. The following video formats are supported
      optimized:

      MPEG-1, MPEG-2, MPEG-4 ASP (MPEG-4 Part 2), H.264/MPEG-4 AVC and
      VC-1, WMV3/WMV9

      

      There are hundreds of different graphics cards, so the setting of
      one user does not necessarily have to be the same as the setting
      of another user. Here everyone has to test which setting is the
      best, otherwise if you only cut smaller videos from time to time
      and then use other codecs than the ones mentioned above, it is
      recommended to use the default settings without all the hardware
      tests.

      

      Sam