[FFmpeg-trac] #2504(undetermined:new): Audio glitches and distortion when recording and direct play

[FFmpeg]

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

Comment (by cehoyos):

 The following assumes you have a toolchain installed (gcc and make) and
 git, when I write {{{mplayer out.wav}}} you can use any program to test if
 {{{out.wav}}} plays fine or with distortions.
 You should not be administrator and you should not install any of the
 binaries you build.
 Instead of {{{./configure && make ffmpeg}}} you can use above (long)
 configure line which speeds up compilation very significantly, but will
 sometimes fail linking, then just run {{{./configure && make ffmpeg}}}
 Instead of {{{make ffmpeg}}}, you can always use {{{make -j16 ffmpeg}}}
 depending on how many CPUs you have.
 First checkout the FFmpeg sources:
 {{{
 $ git clone git://source.ffmpeg.org/ffmpeg.git ffmpeg
 }}}
 Change into the FFmpeg directory:
 {{{
 $ cd ffmpeg
 }}}
 Compile current FFmpeg to verify the problem:
 {{{
 $ ./configure && make ffmpeg
 }}}
 Record:
 {{{
 $ ffmpeg -f alsa -ac 2 -i hw:0,0 -y out.wav
 }}}
 Test for distortions:
 {{{
 $ mplayer out.wav
 }}}
 (You should hear distortions)
 Start the bisect:
 {{{
 $ make distclean && git bisect bad
 }}}
 (Say ''yes'')
 Checkout the presumably working version:
 {{{
 $ git checkout f2f35d3
 }}}
 Build:
 {{{
 $ ./configure && make ffmpeg
 }}}
 Record:
 {{{
 $ ffmpeg -f alsa -ac 2 -i hw:0,0 -y out.wav
 }}}
 Test for distortions:
 {{{
 $ mplayer out.wav
 }}}
 (Should sound fine)
 Tell git that it works:
 {{{
 $ make distclean && git bisect good
 }}}

 Now you start with the recursive process:
 {{{
 $ ./configure && make ffmpeg
 $ ffmpeg -f alsa -ac 2 -i hw:0,0 -y out.wav
 $ mplayer out.wav
 }}}
 If you hear distortions, you use:
 {{{
 $ make distclean && git bisect bad
 }}}
 If you did not hear distortions, tell git everything is fine:
 {{{
 $ make distclean && git bisect good
 }}}

 Unfortunately, git will sometimes try to let you test versions that do not
 contain FFmpeg, if {{{git bisect skip}}} does not help you, post here and
 I will support you.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2504#comment:31>
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