Recherche avancée

Sur d’autres sites (6875)

• VP9 tiled encoding for view-port dependent 360-degree VR streaming

  28 janvier 2021, par Victor Coyter

  I am trying to use libvpx-vp9 to encode a 360-degree VR video and generate multi-bitrate viewport-dependent playlist, that is :

  


  

  • A video stream could be splitted in to n*m tiles (e.g., 8x8)

  


  • Users may fetch those high-resolution tiles which insides their view-port via HTTP webm

  


  • and fetch low-resolution tiles which outsides their view-port

  


  • Finally, combine the video (without decoding) and render with OpenGL shaders

  


  


  Similar ideas like OMAF has been implemented by Intel / fraunhofer hhi, but they were using H.265.

  


  Is that possible to implement in VP9 ?

  


  The tiles in VP9 is designed to accelerate the encoding process by multi-threading, but as per defined in VP9 bitstream specifications, a tile is a "rectangular region of the frame that could be able to be decoded and encoded independently"

  


  I can find that libvpx provide options : --tile-rows and --tile-column and can successfully run them, while they indeed use multi-thread to encode.

  


• udpsrc doesn't work on 2 NIC & Port mirror linux setup (gstreamer/vlc/ffmpeg)

  28 janvier 2021, par kepitto

  I've tried a lot of stuff, but I can't seem to get it to work. (Same problem exists with ffmpeg/vlc)

  


  Basically, I can't get the UDP Stream directly into a videotool. I can verify the data coming in through tcpdump/wireshark etc. and i can also create the videofiles through gstreamer/ffmpeg afterwards, but I can't use the udp source as input.

  


  The current setup is the following :
The camera streams MJPEG through UDP to a fixed address & port. I port mirrored the data from the camera, so that I can verify the data coming in through wireshark on a 3rd device.

  


  The reason behind doing this is that multicast is not supported, so I need a way to get the data on 2 devices through unicast. Port mirroring seemed like a viable solution.

  


  Am I missing something here ? What do I need to do to get this working ?
I thought maybe it's due to the two networkinterface setup as I use 1x usb to ethernet for the port mirror and 1x ethernet for the web, but disconnecting the other shows no difference.
The routing seems correct too : "ip route get camera.ip" returns that the routing is through the usb to ethernet on my static ip.

  


  Example of an attempt :

  


  Gst-launch-1.0 udpsrc port=streamingport(confirmed through wireshark) ! jpegdec ! videorate ! video/x-raw,framerate=30/1 ! autovideosink (does not work)

  


  Gst-launch-1.0 filesrc location=hexdumpfile.txt ! jpegdec ! videorate ! video/x-raw,framerate=30/1 ! autovideosink (does work)

  


• lavc/aarch64 : port HEVC add_residual NEON

  10 janvier 2021, par Reimar Döffinger

  lavc/aarch64 : port HEVC add_residual NEON
  Speedup is fairly small, around 1.5%, but these are fairly simple.
  Signed-off-by : Josh Dekker <josh@itanimul.li>
  

  • [DH] libavcodec/aarch64/hevcdsp_idct_neon.S
  • [DH] libavcodec/aarch64/hevcdsp_init_aarch64.c