[FFmpeg-trac] #2504(avdevice:new): Audio glitches and distortion when recording alsa

FFmpeg trac at avcodec.org
Thu Jun 27 10:06:01 CEST 2013


#2504: Audio glitches and distortion when recording alsa
------------------------------------+------------------------------------
             Reporter:  MrNice      |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  important   |                Component:  avdevice
              Version:  git-master  |               Resolution:
             Keywords:  regression  |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
------------------------------------+------------------------------------

Comment (by cehoyos):

 Replying to [comment:95 MrNice]:
 > I am running the bisec and did more than 100 loops.

 Generally, everything >15 seems incorrect, but in this specific case, only
 ten steps are necessary (there are less than 2^10^ versions between
 743b389 and f2f35d3).

 Why didn't you follow the original path that we worked on above?
 First test the versions that we selected to make sure nothing went wrong
 (if the first mplayer doesn't sound good or the second doesn't sound bad,
 the bisecting will not help):
 {{{
 $ make distclean
 $ git bisect reset
 $ git checkout master
 $ git bisect start
 $ git checkout 743b389
 $ ./configure ...
 $ ./ffmpeg -f alsa -ac 2 -i hw:0,0 -y -t 10 out.wav
 $ mplayer out.wav
 $ make distclean && git bisect good
 $ git checkout f2f35d3
 $ ./configure ...
 $ ./ffmpeg -f alsa -ac 2 -i hw:0,0 -y -t 10 out.wav
 $ mplayer out.wav
 $ make distclean && git bisect bad
 }}}
 Then start bisecting:
 {{{
 $ ./configure ...
 $ ./ffmpeg -f alsa -ac 2 -i hw:0,0 -y -t 10 out.wav
 $ ./mplayer out.wav
 $ git bisect good/bad
 }}}
 If you use the "long" configure line, this should not take more than 15
 minutes, with {{{./configure && make}}}, it depends on your hardware.

 Are you aware that you can speed up compilation time depending on the
 number of CPUs installed?
 {{{./configure ... && make -j16 ffmpeg}}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2504#comment:96>
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