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• Revision bdd7f74c3f : Added initial support for 16-bit framebuffers. Changes in this patch are only e

  22 avril 2014, par Peter de Rivaz

  Changed Paths :
   Modify /configure

  
   Modify /vp9/common/vp9_alloccommon.c

  
   Modify /vp9/common/vp9_blockd.h

  
   Modify /vp9/common/vp9_common.h

  
   Modify /vp9/common/vp9_convolve.c

  
   Modify /vp9/common/vp9_convolve.h

  
   Modify /vp9/common/vp9_idct.c

  
   Modify /vp9/common/vp9_idct.h

  
   Modify /vp9/common/vp9_loopfilter.c

  
   Modify /vp9/common/vp9_loopfilter_filters.c

  
   Modify /vp9/common/vp9_onyxc_int.h

  
   Modify /vp9/common/vp9_reconinter.c

  
   Modify /vp9/common/vp9_reconinter.h

  
   Modify /vp9/common/vp9_reconintra.c

  
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/common/vp9_scale.c

  
   Modify /vp9/common/vp9_scale.h

  
   Modify /vp9/decoder/vp9_decodeframe.c

  
   Modify /vp9/encoder/vp9_aq_variance.c

  
   Modify /vp9/encoder/vp9_dct.c

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_encodemb.c

  
   Modify /vp9/encoder/vp9_encoder.c

  
   Modify /vp9/encoder/vp9_encoder.h

  
   Modify /vp9/encoder/vp9_extend.c

  
   Modify /vp9/encoder/vp9_firstpass.c

  
   Modify /vp9/encoder/vp9_lookahead.c

  
   Modify /vp9/encoder/vp9_lookahead.h

  
   Modify /vp9/encoder/vp9_mcomp.c

  
   Modify /vp9/encoder/vp9_rdopt.c

  
   Modify /vp9/encoder/vp9_sad.c

  
   Modify /vp9/encoder/vp9_temporal_filter.c

  
   Modify /vp9/encoder/vp9_variance.c

  
   Modify /vp9/encoder/vp9_variance.h

  
   Modify /vp9/vp9_cx_iface.c

  
   Modify /vp9/vp9_iface_common.h

  
   Modify /vpx/src/vpx_encoder.c

  
   Modify /vpx/src/vpx_image.c

  
   Modify /vpx/vp8cx.h

  
   Modify /vpx/vpx_encoder.h

  
   Modify /vpx/vpx_image.h

  
   Modify /vpx_mem/vpx_mem.c

  
   Modify /vpx_mem/vpx_mem.h

  
   Modify /vpx_scale/generic/yv12config.c

  
   Modify /vpx_scale/generic/yv12extend.c

  
   Modify /vpx_scale/yv12config.h

  
   Modify /vpxdec.c

  
   Modify /vpxenc.c

  
  
  Added initial support for 16-bit framebuffers.

  Changes in this patch are only enabled if configured with
  — enable-experimental —enable-vp9_high

  Using a encoder command line argument of —input-shift=0 tells the coder
  to work with 16bit framebuffers.
  The output should be identical to before. Some features (such as input
  image resizing) are not yet supported in 16bit mode.

  Specifically, the behavior of the input-shift parameter is as follows :
  * No argument : Behaviour as before, using 8bit frame buffers
  * —experimental-bitstream —profile=2 —input-shift=0 : Uses
  16bit frame buffers to store 8-bit data, should give identical output
  to before.
  * —experimental-bitstream —profile=2 —input-shift=2 —bit-depth=1 : Uses
  16bit frame buffers to store 10-bit data, encodes a version 2 stream
  with bitdepth 10
  * —experimental-bitstream —profile=2 —input-shift=4 —bit-depth=2 : Uses
  16bit frame buffers to store 12-bit data, encodes a version 2 stream
  with bitdepth 12

  The decoder has an —output-shift argument which should be used when
  decoding profile 2 streams.

  So far support for the following has been added :
  Intra filtering
  Deblocking
  Motion compensation
  Variance calculation
  Sad calculation
  Transform

  Change-Id : If345c88234aafdd40caea0d88935b1f07aaebe22

• Shifting audio in MPEG4 content and manipulating atoms

  10 janvier 2018, par LLL

  1. Shift audio

  I use ffmpeg / avconv quite often ... and usually I hate it.
  Those tools do what they are instructed to do about 30% of the time. I could give you countless examples but I don’t want to start flame war, so please help me with my current problem (really easy one).

  I wanted to shift audio (content is standard mp4 file with aac and h264 tracks), so I have found a "highly upvoted" solution :

  https://superuser.com/a/983153/758887

  the only problem with it is that it doesn’t work. I downloaded latest stable ffmpeg (even on windows as in the thread, so it’s version was 3.4.1) and executed command without changing literaly anything :

  ffmpeg.exe -i "movie.mp4" -itsoffset 3.84 -i "movie.mp4" -map 0:v -map 1:a -vcodec copy -acodec copy "movie-audio-delayed.mp4"

  Result was no shift (I expected audio to be 3.84s late).

  2. Remove MPEG4 atoms

  I would be also grateful if you could recommend some tool for removing MPEG4 boxes from content. For examining MPEG4 content I use MP4 Explorer / Codec Visa (limited) on Windows and AtomicParsley on Linux, however they only print atoms and I would like to edit / remove them. For example MP4Box can remove whole moov->track with "-rem" option but what if I would like to remove moov->track->edts only ?

• Fallback input for ffmpeg

  22 septembre 2018, par Daniel Cantarin

  I’m doing some transcoding from a third-party remote input stream that I do not control.

  This input stream has errors from time to time, that I would like to mitigate before sending the stream to my transcoding pipeline, avoiding this way some possible problems in the output.

  I have several ideas regarding different problems. But the most basic scenario I would like to set up is as follows : when the stream is down, or it somehow loses some frames, I want to fill that video gap with a secondary input (like a blank screen, for example).

  For this simple task, I would like to use ffmpeg. I know it can mix, let’s say, an input stream with a fullscreen black square static image. However, I have to deal with this other condition : ffmpeg would run in the same infraestructure for the actual transcoding pipeline. That infraestructure must use its computing power for rendering the output. So, whatever ffmpeg command I end up using should use the minimum possible computing power.

  My actual problem : if I use -vcodec copy, in order to use minimum CPU, I can’t alter the original stream. But if I alter the original stream (by mixing it with some other stream), the operation uses CPU.

  My question : Is there a way to use -vcodec copy, but with a fallback input (instead of a mixed one) for when there are video gaps in the primary stream ?

  Thanks in advance.