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• Why are v0, v1, and v2 of ffmpeg still under active development ? What happened to ppa:jon-severinsson/ffmpeg ?

  12 avril 2015, par cxrodgers

  I know about the long history of ffmpeg and libav. Personally, I preferred to use Jon Severinsson’s PPA, as suggested in many answers here on stackoverflow or askubuntu. However, recently this PPA seems to have gone down recently (this page, which is the link everyone always gives, is dead). I don’t see if he put up a newer version, although I admit I find launchpad hard to navigate. Did it get replaced with this one from Doug McMahon or this one from Sam Rog ?

  Ok, so maybe I need to download it myself. I visit the releases page for ffmpeg, and there seems to be simultaneous development of releases from v2 (2.6.2), v1 (1.2.12, from February), and v0 (0.10.16, from March of this year). 0.10 isn’t even the newest of the v0 series, and yet it seems to be the most recently updated of that series, and (coincidentally ?) also the version that I most recently got from the PPA. Admittedly this was on a slightly older distribution (Linux Mint 16).

  ffmpeg -version
  
  ffmpeg version 0.10.12-7:0.10.12-1~saucy1

  So, which version should I download, now that the PPA is gone ? Does it depend on the distribution I’m using ?

• Revision fd070220ff : Adjust active maxq for GF groups. Currently disabled by default : enabled using

  21 janvier 2015, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_firstpass.c

  
   Modify /vp9/encoder/vp9_firstpass.h

  
  
  Adjust active maxq for GF groups.

  Currently disabled by default : enabled using
  #define GROUP_ADAPTIVE_MAXQ

  In this patch the active max Q is adjusted for each GF
  group based on the vbr bit allocation and raw first pass
  group error.

  This will tend to give a lower q for easy sections
  and a higher value for very hard sections. As such it is
  expected to improve quality in some of the easier
  sections where quality issues have been reported.

  This change tends to hurt overall psnr but help
  average psnr. SSIM also shows a small gain.

  Average results for derf, yt, std-hd and yt-hd test sets were
  as follows (%change for average psnr, overal psnr and ssim) :-

  derf +0.291, - 0.252, -0.021
  yt +6.466, -1.436, +0.552
  std-hd +0.490, +0.014, +0.380
  yt-hd +5.565, - 1.573, +0.099

  Change-Id : Icc015499cebbf2a45054a05e8e31f3dfb43f944a

• Revision 422d7bc918 : Relax maximum Q for extreme overshoot. Added code to relax the active maximum Q

  28 octobre 2014, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_firstpass.c

  
  
  Relax maximum Q for extreme overshoot.

  Added code to relax the active maximum Q in response
  to extreme local overshoot to reduce bandwidth peaks.

  The impact is small in metrics terms, but it this helps reduce
  bandwidth spikes and overall overshoot in a number of
  clips in our tests sets (especially the YT test set).

  In particular this should help prevent very big spikes where a clip
  is mainly easy but has a short hard section. In such a case a choice
  of maximum Q for the clip as a whole may allow us to hit the overall
  target rate but give some extreme spikes. The chunked encoding in YT
  mitigates this problem but it can show up where a longer clip is
  coded as a single chunk.

  Change-Id : I213d09950ccb8489d10adf00fda1e53235b39203