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• lavd/v4l2 : do not fail when VIDIOC_ENUMSTD returns ENODATA

  18 août 2014, par Andre Wolokita

  lavd/v4l2 : do not fail when VIDIOC_ENUMSTD returns ENODATA
  As of September 14 2012, v4l_enumstd() will return ENODATA
  
  when a device’s std field is set to 0. That is, the device
  
  does not have a standard format. In order to properly
  
  handle this case, v4l2_set_parameters should catch the
  
  ENODATA code and break instead of failing.
  Below is the v4l2-core commit describing this change.
  >>commit a5338190efc7cfa8c99a6856342a77d21c9a05cf
  
  >>Author : Hans Verkuil <hans.verkuil@cisco.com>
  
  >>Date :   Fri Sep 14 06:45:43 2012 -0300
  
  >>
  
  >>    [media] v4l2-core : tvnorms may be 0 for a given input, handle that case
  
  >>
  
  >>    Currently the core code looks at tvnorms to see whether ENUMSTD
  
  >>    or G_PARM should be enabled. This is not a good check for drivers
  
  >>    that support the STD API on one input and the DV Timings API on another.
  
  >>    In that case tvnorms may be 0.
  
  >>    Instead check whether s_std is present (for ENUMSTD) or whether g_std or
  
  >>    current_norm is present for g_parm.
  
  >>    Also, in the enumstd core function return ENODATA if tvnorms is 0,
  
  >>    because in that case the current input does not support the STD API
  
  >>    and ENUMSTD should return ENODATA for that.
  
  >>
  
  >>    Signed-off-by : Hans Verkuil <hans.verkuil@cisco.com>
  
  >>    Reviewed-by : Sakari Ailus <sakari.ailus@iki.fi>
  
  >>    Signed-off-by : Mauro Carvalho Chehab <mchehab@redhat.com>
  

  • [DH] libavdevice/v4l2.c

• Grep for a number between a certain range - Checking WAV Quality

  11 août 2014, par BT643

  I’m trying to write a regular expression (to be used in conjunction with ffmpeg, which can check that a WAV file is over a certain quality.

  The minimum should be :

  Audio Channels : 2 (Stereo)
  Audio Sample Rate : 44,100 Hz
  Audio Bitrate : 1411 Kbps
  Audio Bit Depth : 16 bit
  

  So I’ve tried the following commands so far :

  • /usr/local/bin/ffmpeg -i "/path/to/file.wav" 2>&1 | egrep 'stereo|2 channels'

  This works fine to get a stero (2 channel) WAV. I’m getting issues with the next part, searching between a range of numbers.

  • /usr/local/bin/ffmpeg -i "/path/to/file.wav" 2>&1 | egrep 'stereo|2 channels' | egrep '[41000-196000] Hz'

  Obviously this just searches each number individually, so it’s finding results if there’s a 4 OR 1 OR 0 OR 0 OR 0 etc...

  The bit rate and bit depth just needs to be OVER 1411 and 16 respectively.

  Thanks

  EDIT -
  Here’s the ffmpeg output for a low quality WAV which should be rejected :

  ffmpeg version git-2012-05-22-27127eb Copyright (c) 2000-2012 the FFmpeg developers
 built on May 22 2012 12:27:21 with gcc 4.6.1
 configuration: --enable-gpl --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-nonfree --enable-postproc --enable-version3 --enable-x11grab
 libavutil      51. 53.100 / 51. 53.100
 libavcodec     54. 21.101 / 54. 21.101
 libavformat    54.  6.100 / 54.  6.100
 libavdevice    53.  4.100 / 53.  4.100
 libavfilter     2. 75.100 /  2. 75.100
 libswscale      2.  1.100 /  2.  1.100
 libswresample   0. 15.100 /  0. 15.100
 libpostproc    52.  0.100 / 52.  0.100
[wav @ 0x355b140] max_analyze_duration 5000000 reached at 5056000
Guessed Channel Layout for  Input Stream #0.0 : stereo
Input #0, wav, from '/path/to/file.wav':
 Duration: 00:02:28.47, bitrate: 512 kb/s
   Stream #0:0: Audio: pcm_u8 ([1][0][0][0] / 0x0001), 32000 Hz, stereo, u8, 512 kb/s

• It’s Piwik Analytics Survey time : Your Opinion Matters !

  10 juillet 2014, par Piwik Core Team — Community

  It’s been almost two years since our last survey. We were so happy to get the participation we did from the community last time and hope that you will once again share your thoughts !

  

  Fill in the survey

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  • New app design with Morpheus theme
  • Piwik Marketplace for Plugins
  • Visitor Profile
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  • Theming
  • Migrated from SVN to Github !
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  Now it is time to ask for your opinion again. Sure it’s only 20 short questions, but your time you take and energy you place in this endeavour will shape Piwik development and features for the near future. We really look forward to your ideas, your opinions and your suggestions. To get started click the box (or link) below :

  

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