[alsa-devel] FIXED by substituting 1.0.19 pcm_lib.c for 1.0.21 pcm_lib.c -> Re: ALSA 1.0.20 PCM Capture Problem (Does not happen on ALSA 1.0.19)

[Robert Krakora]

I grabbed ALSA 1.0.20 and attempted to capture video from my Creative
USB webcam and audio from my analog audio microphone. To my surprise
there was audio being captured but only in bits and pieces, nothing
audible. If I recorded the audio and played it back it sound like
broken audio. I noticed this in the release notes:

[ALSA] pcm-midlevel: Add more strict buffer position checks based on jiffies

I assumed it had something to do with changes made in pcm_lib.c, so I
replaced the ALSA 1.0.20 version of this file with the ALSA 1.0.19
version, rebuilt and I am now able to capture audio again from my
analog microphone.

I filed Bug Report 0004523 describing this problem.



On Tue, May 12, 2009 at 5:16 PM, Robert Vincent Krakora
<rob.krakora at messagenetsystems.com> wrote:
> Hello,
>
> I am utilizing an external mic on my machine in conjunction with a
> VF0560 Live! Cam Optia AF webcam.  I am running CentOS 5.3 with the
> kernel listed below and ALSA 1.0.20.  I using the machine to stream
> video with VLC 9.9 (see further below).  VLC spits out the following on
> the console of my machine whist capturing A/V and serving it up on the
> network...ALSA 1.0.19 did not exhibit this problem while streaming it
> did lock up after 20 minutes or so (audio could be heard on the VLC or
> mplayer client with ALSA 1.0.19...just bits and pieces of audio every
> now and then with ALSA 1.0.20.  V4L is not the culprit here as video
> streams and can be received without incident if I do not also capture
> audio.  The mic is plugged into the onboard sound on the motherboard.  I
> have not yet tried my USB mic with ALSA 1.0.20, but I will try it later
> tonight.  Any and all help would be greatly appreciate.  Thanks in advance.
>
> [00000473] main audio output warning: audio drift is too big (-146765),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-29715)
> [00000473] main audio output warning: audio drift is too big (-150692),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30980)
> [00000493] main spu text debug: looking for text renderer module: 3
> candidates
> [00000493] freetype spu text error: failed to load font file
> /usr/share/fonts/truetype/freefont/FreeSerifBold.ttf
> [00000493] main spu text debug: using text renderer module "svg"
> [00000493] main spu text debug: TIMER module_Need() : 29.750 ms - Total
> 29.750 ms / 1 intvls (Avg 29.750 ms)
> [00000492] main blend debug: looking for video blending module: 1 candidate
> [00000492] blend blend debug: chroma: YUVA -> I420
> [00000492] main blend debug: using video blending module "blend"
> [00000492] main blend debug: TIMER module_Need() : 0.433 ms - Total
> 0.433 ms / 1 intvls (Avg 0.433 ms)
> [00000473] main audio output warning: audio drift is too big (-147017),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-29763)
> [00000473] main audio output warning: audio drift is too big (-147157),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30302)
> [00000473] main audio output warning: audio drift is too big (-150434),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30931)
> [00000473] main audio output warning: buffer is 114796 in advance,
> triggering downsampling
> [00000473] main audio output warning: audio drift is too big (-261628),
> clearing out
> [00000473] main audio output warning: timing screwed, stopping resampling
> [00000473] main audio output warning: mixer start isn't output start
> (-53788)
> [00000473] main audio output warning: audio drift is too big (-146580),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-29711)
> [00000473] main audio output warning: audio drift is too big (-150686),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30979)
> [00000473] main audio output warning: audio drift is too big (-146733),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-29708)
> [00000473] main audio output warning: audio drift is too big (-146978),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30267)
> [00000473] main audio output warning: audio drift is too big (-150569),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30445)
> [00000473] main audio output warning: buffer is 114650 in advance,
> triggering downsampling
> [00000473] main audio output warning: audio drift is too big (-261447),
> clearing out
> [00000473] main audio output warning: timing screwed, stopping resampling
> [00000473] main audio output warning: mixer start isn't output start
> (-54265)
> [00000473] main audio output warning: audio drift is too big (-146518),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-29699)
> [00000473] main audio output warning: audio drift is too big (-146731),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30220)
> [00000473] main audio output warning: audio drift is too big (-150880),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30505)
> [00000473] main audio output warning: audio drift is too big (-146644),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30203)
> [00000473] main audio output warning: audio drift is too big (-146701),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-29702)
> [00000473] main audio output warning: audio drift is too big (-150683),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30979)
> [00000473] main audio output warning: audio drift is too big (-146706),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-29703)
> [00000473] main audio output warning: audio drift is too big (-146916),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30255)
> [00000473] main audio output warning: audio drift is too big (-150819),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-31005)
> [00000473] main audio output warning: audio drift is too big (-147003),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-29760)
> [00000473] main audio output warning: audio drift is too big (-146886),
> clearing out
> [00000473] main audio output warning: mixer start isn't output start
> (-30250)
> [00000473] main audio output warning: audio drift is too big (-150552),
> clearing out
>
>
> [root at vizioroom105 ~]# uname -a
> Linux vizioroom105.msgnet.com 2.6.27.10 #2 SMP Thu Jan 22 09:09:44 EST
> 2009 x86_64 x86_64 x86_64 GNU/Linux
>
> [root at vizioroom105 ~]# arecord -l
> **** List of CAPTURE Hardware Devices ****
> card 0: AF [VF0560 Live! Cam Optia AF], device 0: USB Audio [USB Audio]
>  Subdevices: 1/1
>  Subdevice #0: subdevice #0
> card 1: SB [HDA ATI SB], device 0: ALC883 Analog [ALC883 Analog]
>  Subdevices: 1/1
>  Subdevice #0: subdevice #0
> card 1: SB [HDA ATI SB], device 1: ALC883 Digital [ALC883 Digital]
>  Subdevices: 1/1
>  Subdevice #0: subdevice #0
> card 1: SB [HDA ATI SB], device 2: ALC883 Analog [ALC883 Analog]
>  Subdevices: 0/1
>  Subdevice #0: subdevice #0
>
>
> [root at vizioroom105 ~]# su silentm -c "/usr/bin/vcamera -vvvvv -I dummy
> -V dummy --dscp=0x01 v4l2:// :v4l2-dev=/dev/video0 :v4l2-adev=hw.1,0
> :v4l2-width=720 :v4l2-height=480 :v4l2-standard=0 --sout
> '#transcode{vcodec=mp4v,vb=6000,fps=30,scale=1,acodec=mpga,ab=32,channels=1}:duplicate{dst=rtp{mux=ts,port=1234,sdp=rtsp://192.168.1.179:8080/test.sdp}}'
> vlc://quit"
>
> Best Regards,
> --
> Rob Krakora
> Senior Software Engineer
> MessageNet Systems
> 101 East Carmel Dr. Suite 105
> Carmel, IN 46032
> (317)566-1677 Ext. 206
> (317)663-0808 Fax
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel at alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>
>



-- 
Rob Krakora
Senior Software Engineer
MessageNet Systems
101 East Carmel Dr. Suite 105
Carmel, IN 46032
(317)566-1677 Ext. 206
(317)663-0808 Fax