[FFmpeg-trac] #615(FFmpeg:new): ALSA buffer xrun

[FFmpeg]

#615: ALSA buffer xrun
--------------------------------------+---------------------------------
               Reporter:  burek       |                  Owner:  michael
                   Type:  defect      |                 Status:  new
               Priority:  normal      |              Component:  FFmpeg
                Version:  git-master  |               Keywords:
             Blocked By:              |               Blocking:
Reproduced by developer:  0           |  Analyzed by developer:  0
--------------------------------------+---------------------------------
 when grabbing video+audio from usb webcam, this error always appear, no
 matter what output muxer format is chosen: "ALSA buffer xrun"

 i've tried with .avi, .ts, .flv, .mkv, and all give the similar output:

 {{{
 ffmpeg -y -re \
         -f video4linux2 -r 30 -s qvga -i /dev/v4l/by-id/usb-
 046d_0809_33A881A3-video-index0 \
         -f alsa -ar 44100 -ac 2 -i default:CARD=Intel \
         out.flv

 ffmpeg version N-34519-g54a09f1, Copyright (c) 2000-2011 the FFmpeg
 developers
   built on Nov  6 2011 12:46:05 with gcc 4.6.1
   configuration: --enable-static --enable-shared --enable-gpl --enable-
 nonfree --enable-postproc --enable-libx264 --enable-libaacplus --enable-
 libmp3lame --enable-libv4l2 --enable-libvo-aacenc --enable-version3
   libavutil    51. 23. 0 / 51. 23. 0
   libavcodec   53. 28. 0 / 53. 28. 0
   libavformat  53. 19. 0 / 53. 19. 0
   libavdevice  53.  4. 0 / 53.  4. 0
   libavfilter   2. 47. 0 /  2. 47. 0
   libswscale    2.  1. 0 /  2.  1. 0
   libpostproc  51.  2. 0 / 51.  2. 0
 [video4linux2,v4l2 @ 0x2247980] Estimating duration from bitrate, this may
 be inaccurate
 Input #0, video4linux2,v4l2, from '/dev/v4l/by-id/usb-046d_0809_33A881A3
 -video-index0':
   Duration: N/A, start: 27263.653187, bitrate: 27648 kb/s
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 320x240,
 27648 kb/s, 30 tbr, 1000k tbn, 30 tbc
 [alsa @ 0x2242040] Estimating duration from bitrate, this may be
 inaccurate
 Input #1, alsa, from 'default:CARD=Intel':
   Duration: N/A, start: 1320593764.890759, bitrate: N/A
     Stream #1:0: Audio: pcm_s16le, 44100 Hz, 2 channels, s16, 1411 kb/s
 [buffer @ 0x2297f20] w:320 h:240 pixfmt:yuv420p tb:1/1000000 sar:0/1
 sws_param:
 Output #0, flv, to 'out.flv':
   Metadata:
     encoder         : Lavf53.19.0
     Stream #0:0: Video: flv1 ([2][0][0][0] / 0x0002), yuv420p, 320x240,
 q=2-31, 200 kb/s, 1k tbn, 30 tbc
     Stream #0:1: Audio: mp3 ([2][0][0][0] / 0x0002), 44100 Hz, 2 channels,
 s16, 128 kb/s
 Stream mapping:
   Stream #0.0 -> #0.0 (rawvideo -> flv)
   Stream #1.0 -> #0.1 (pcm_s16le -> libmp3lame)
 Press [q] to stop, [?] for help
 [alsa @ 0x2242040] ALSA buffer xrun.
 ALSA buffer xrun. 6 q=2.6 size=      34kB time=00:00:01.48 bitrate=
 185.4kbits/s
 ALSA buffer xrun. 8 q=2.6 size=     103kB time=00:00:03.52 bitrate=
 240.2kbits/s
 frame=   78 fps=  8 q=2.8 Lsize=     252kB time=00:00:04.91 bitrate=
 421.2kbits/s
 video:171kB audio:77kB global headers:0kB muxing overhead 1.801323%
 root at strumf:~/videos/tests/mpegts# ^C
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/615>
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