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• Revision 1ed0e1beb5 : Move SVC per-frame loop from sample app into libvpx proper SVC multiple layer p

  23 octobre 2013, par Ivan Maltz

  Changed Paths :
   Modify /examples.mk

  
   Modify /libs.mk

  
   Add /test/svc_test.cc

  
   Modify /test/test.mk

  
   Modify /vp9/common/vp9_onyx.h

  
   Modify /vp9/encoder/vp9_onyx_if.c

  
   Modify /vp9/vp9_cx_iface.c

  
   Modify /vp9_spatial_scalable_encoder.c

  
   Modify /vpx/exports_enc

  
   Add /vpx/src/svc_encodeframe.c

  
   Add /vpx/svc_context.h

  
   Modify /vpx/vp8cx.h

  
   Modify /vpx/vpx_codec.mk

  
  
  Move SVC per-frame loop from sample app into libvpx proper

  SVC multiple layer per frame encoding is invoked with vpx_svc_init and
  vpx_svc_encode. These interfaces are designed to be invoked from ffmpeg.
  Additional improvements :
   make dummy frame handling a bit more explicit
   fixed bug with single layer encodes
   track individual frame sizes and psnrs instead of averages
   parameterized quantizer, 16th scalefactors, more logging,
   enabled single layer encodes to generate baseline
   include new mode for 3 layer I frame with 5 total layers

  Change-Id : I46cfa600d102e208c6af8acd6132e0cc25cda8d4

• Can OpenCV decode H264 - MPEG-4 AVC (part 10)

  15 avril 2015, par Sergiy

  I am trying to use OpenCV (python bindings) to connect to a UDP multicast and recover individual received frames for post-processing.

  I can connect to my multicast via VLC, and VLC displays the broadcast with no issues at all. VLC reports that the codec it uses for decoding is H264 - MPEG-4 AVC (part 10).

  When I try to decode using OpenCV, I do see my video stream, but many frames appear fragmented. The frames appear as if the last line of pixels just got repeated to fill in the rest of the image (sometimes 75% or more of the whole image). OpenCV reports decoding errors (error while decoding MB ...., bytestream ).

  Is there any way to force OpenCV to use whatever codec VLC is using ? I tried to specify the specific codec to use in my code for OpenCV but it seems to have no effect.

  The code I am using is below :

  import numpy as np
  
  import cv2
  
  from cv2 import cv
  
  
  
  cap = cv2.VideoCapture()
  
  cap.set(cv.CV_CAP_PROP_FOURCC, cv.CV_FOURCC('A','V','C','1')) 
  
  cwi=cap.open(r'myurlandport')
  
  
  
  counter = 0
  
  
  
  while(cap.isOpened()):
  
  
  
      ret, frame = cap.read()
  
  
  
  
  
      counter += 1
  
  
  
      if counter % 30 == 0:
  
          cv2.imshow('frame', frame)
  
          if cv2.waitKey(1) & 0xFF == ord('q'):
  
              break
  
  
  
  cap.release()
  
  cv2.destroyAllWindows()

• Gstreamer preserve timestamp when encoding ts segments

  1er juillet 2021, par Guru Govindan

  I have a series of ts files(h265) which are part of a m3u8 manifest which are fed into the pipeline through fdsrc. I use the following pipeline to transcode them to H264 to be played on a Hlsjs web browser.

  


  cat 2021-06-30T00-55-41Z_2000000.ts | gst-launch-1.0  -q mpegtsmux name=mux ! fdsink fd=1 fdsrc ! tsdemux name=demux demux. ! queue ! h265parse ! nvh265dec ! videoconvert ! videoscale ! video/x-raw,width=640,height=360 ! nvh264enc ! mux.


  


  The individual ts segments are transcoded successfully and can be played.

  


  However the DTS is out of aligment and when these ts segments are played as part of the hls manifest, it is not able to play as DTS is out of order.

  


  [mpegts @ 0x7fb69100a400] DTS 6496420096 < 6496446847 out of order
[hls @ 0x7fb69580ea00] DTS 6496420096 < 6496446847 out of order


  


  In FFMPEG we have copyts to preserve the timestamp.
Is there something similar in gstreamer to preserve the timestamp ? Or atleast generate a timestamp with the current time so that the player doesnt complain ?

  


  I tried fdsrc do-timestamp=true but that didnt work.

  


  I appreciate any help in this.

  


  Best