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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

• Merging 2 videos with overlay causes async problems

  3 novembre 2014, par Gnagy

  I’m using following FFMPEG command to merge 2 MKV inputs with the overlay parameter.
  The result should be one output with input1 on top of input2.
  In the process, the output should be webm.
  Both inputs are of the same length (with a margin of a second).

  ffmpeg -i input1.mkv -i input2.mkv -y -filter_complex [0:v]select=1, setpts=PTS-STARTPTS, scale=400:300, pad=400:600 [top]; [1:v]select=1, setpts=PTS-STARTPTS, scale=400:300 [bottom]; [top][bottom] overlay=0:300 [out]; [0:a:0][1:a:0] amerge=inputs=2 [a]; [a] asetpts=PTS-STARTPTS [a] -map [a] -c:v libvpx -crf 10 -b:v 360K -q:v 7 -c:a libvorbis -b:a 32k -map [out] output.webm

  This command does what it’s supposed to do.

  However, the 2 videos are not totally in sync.

  The input1 on the top plays decently while the input2 on the bottom has black frames, slows down or speeds up and causes the audio and video to be out of sync.

  To rule out the individual quality of the inputs, we switched the position of the videos and the top video always plays decently.

  How can we fix this ?

• FFMPEG - speed up/slow down video, add jitter etc

  27 septembre 2019, par Darrell

  I’m trying to put together a Windows script that will process short videos in a folder.
  The videos will be shot at a high frame rate 60+ fps and be about 4-5 secs long.

  Basically I am looking to make various style clips, using fast/slow effects, back and forth etc.
  So, the script might process a video, make it start normal speed, then slow motion. Next video might be normal speed, slomo, normal speed slomo. Next video might be forwards,back, forwards back, slomo.

  See example : (this is a compliation, I’m looking at processing individual videos in a folder.)

  http://www.youtube.com/watch?v=K03IBQZu8SQ

  I’m guessing there is no way to do this, other than splitting a clip using FFMPEG, processing the bits, then merging back together ? I can’t seem to find a way to do it as one clip.