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• Revision 36982 : Certaines valeurs ne passent pas dans presets ... on améliore de ce coté ...

  6 avril 2010, par kent1@… — Log

  Certaines valeurs ne passent pas dans presets ... on améliore de ce coté là
  On affiche les boutons sous les documents même dans le cas d’un retour ajax

• avcodec/h274 : add film grain synthesis routine

  17 août 2021, par Niklas Haas

  avcodec/h274 : add film grain synthesis routine
  This could arguably also be a vf, but I decided to put it here since
  
  decoders are technically required to apply film grain during the output
  
  step, and I would rather want to avoid requiring users insert the
  
  correct film grain synthesis filter on their own.
  The code, while in C, is written in a way that unrolls/vectorizes fairly
  
  well under -O3, and is reasonably cache friendly. On my CPU, a single
  
  thread pushes about 400 FPS at 1080p.
  Apart from hand-written assembly, one possible avenue of improvement
  
  would be to change the access order to compute the grain row-by-row
  
  rather than in 8x8 blocks. This requires some redundant PRNG calls, but
  
  would make the algorithm more cache-oblivious.
  The implementation has been written to the wording of SMPTE RDD 5-2006
  
  as faithfully as I can manage. However, apart from passing a visual
  
  inspection, no guarantee of correctness can be made due to the lack of
  
  any publicly available reference implementation against which to
  
  compare it.
  Signed-off-by : Niklas Haas <git@haasn.dev>
  
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] libavcodec/Makefile
  • [DH] libavcodec/h274.c
  • [DH] libavcodec/h274.h

• Read dumepd RTP stream in libav

  25 mai 2017, par Pawel K

  Hi I am in a need of a bit of a help/guidance because I got stuck in my research.

  The problem :

  How to convert RTP data using either gstreamer or avlib (ffmpeg) in either API (by programming) or console versions.

  Data

  I have RTP dump that comes from RTP/RTCP over TCP so I can get the precise start and stop for each RTP packet in file. It’s a H264 video stream dump.
  The data is in this fashion because I need to acquire the RTCP/RTP interleaved stream via libcurl (which I’m currently doing)

  Status

  I’ve tried to use ffmpeg to consume pure RTP packets but is seems that using rtp either by console or by programming involves "starting" the whole rtsp/rtp session business in ffmpeg. I’ve stopped there and for the time being I didn’t pursue this avenue deeper. I guess this is possible with lover level RTP API like ff_rtp_parse_packet() I’m too new with this lib to do it straight out.

  Then there is the gstreamer It has somewhat more capabilities to do it without programming, but for the time being I’m not able to figure out how to pass it the RTP dump I have.

  I have also tried to do a little bit of a trickery and stream the dump via socat/nc to the udp port and listen on it via ffplay with sdp file as an input, there seems to be some progress the rtp at least gets recognized, but for socat there are loads of packet missing (data sent too fast perhaps ?) and in the end the data is not visualized. When I used nc the video was badly misshapen but at least there were not that much receive errors.

  One way or another the data is not properly visualized.

  I know I can depacketize the data "by hand" but the idea is to do it via some kind of library because in the end there would also be second stream with audio that would have to be muxed together with the video.

  I would appreciate any help on how to tackle this problem.
  Thanks.