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• Revision ed2dc59c1b : Integral projection based motion estimation This commit introduces a new block

  13 février 2015, par Jingning Han

  Changed Paths :
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/encoder/vp9_avg.c

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/x86/vp9_avg_intrin_sse2.c

  
  
  Integral projection based motion estimation

  This commit introduces a new block match motion estimation
  using integral projection measurement. The 2-D block and the nearby
  region is projected onto the horizontal and vertical 1-D vectors,
  respectively. It then runs vector match, instead of block match,
  over the two separate 1-D vectors to locate the motion compensated
  reference block.

  This process is run per 64x64 block to align the reference before
  choosing partitioning in speed 6. The overall CPU cycle cost due
  to this additional 64x64 block match (SSE2 version) takes around 2%
  at low bit-rate rtc speed 6. When strong motion activities exist in
  the video sequence, it substantially improves the partition
  selection accuracy, thereby achieving better compression performance
  and lower CPU cycles.

  The experiments were tested in RTC speed -6 setting :
  cloud 1080p 500 kbps
  17006 b/f, 37.086 dB, 5386 ms ->
  16669 b/f, 37.970 dB, 5085 ms (>0.9dB gain and 6% faster)

  pedestrian_area 1080p 500 kbps
  53537 b/f, 36.771 dB, 18706 ms ->
  51897 b/f, 36.792 dB, 18585 ms (4% bit-rate savings)

  blue_sky 1080p 500 kbps
  70214 b/f, 33.600 dB, 13979 ms ->
  53885 b/f, 33.645 dB, 10878 ms (30% bit-rate savings, 25% faster)

  jimred 400 kbps
  13380 b/f, 36.014 dB, 5723 ms ->
  13377 b/f, 36.087 dB, 5831 ms (2% bit-rate savings, 2% slower)

  Change-Id : Iffdb6ea5b16b77016bfa3dd3904d284168ae649c

• Use FFmpeg to rotate the video based on its metadata ? Why does Android put the wrong metadata ?

  22 juillet 2015, par Mauro Valvano

  I have a website where the user uploads a video.
  For my website i have also an Android application.
  The website creates a thumbnail of each uploaded video (from browser or Android).

  The problem is that for normal videos it’s all OK, but for android my videos are rotated by 90°.

  I think that Android has a bug, because when I see with FFmpeg the video’s metadata, for a normal recorded video I got a rotate=90 value, and for a 90° rotated video, I don’t have anything in the metadata (and the thumbnail is correct).

  Why ?

  This is an image of a normal recorded video (with the phone in portrait mode).

  

  Anyway, I have the metadata in the video, can I create its thumbnail based on its metadata’s rotate value without extracting the metadata and then use ffmpeg to rotate the video on this value ?

  Thank you in advance.

• avformat/omadec : only compute timestamps based on bitrate if its set

  7 février 2015, par Michael Niedermayer

  avformat/omadec : only compute timestamps based on bitrate if its set
  Fixes division by zero
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/omadec.c