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• Merge commit ’671c8785596ea4a45817ba302289004ff456630a’

  14 mars 2014, par Michael Niedermayer

  Merge commit ’671c8785596ea4a45817ba302289004ff456630a’
  * commit ’671c8785596ea4a45817ba302289004ff456630a’ :
  
    bfin : dsputil : Remove unused global variable
  Merged-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/bfin/dsputil_bfin.c

• How can I capture audio AND video simultenaous with ffmpeg from an USB capture device

  5 octobre 2011, par oban

  I'm capturing a video by means of an USB Terratec Grabster AV350 (which is based on the em2860 chip).

  I don't succeed to get the audio when it is played . If I play the captured video with vlc or with ffplay I got only 3 seconds sound and then a silence for the rest of the video ...

  During the capturing I don't get any errors. At the end it indicates the size of the video and audio captured ....

  I'm using the ffmpeg command for this :

  ffmpeg -f alsa -ac 2 -i hw:3 -f video4linux2 -i /dev/video0 -acodec ac3 -ab 128k -vcodec mpeg4 -b 6000k -r 25 test5.avi

  The log is :

  [alsa @ 0x9bcd420]Estimating duration from bitrate, this may be inaccurate
  Input #0, alsa, from 'hw:3' :
  Duration : N/A, start : 69930.998994, bitrate : N/A
  Stream #0.0 : Audio : pcm_s16le, 44100 Hz, 2 channels, s16, 1411 kb/s
  [video4linux2 @ 0x9bf5d30]Estimating duration from bitrate, this may be inaccurate
  Input #1, video4linux2, from '/dev/video0' :
  Duration : N/A, start : 1307111377.654173, bitrate : -2147483 kb/s
  Stream #1.0 : Video : rawvideo, yuyv422, 720x576, -2147483 kb/s, 1000k tbr, 1000k tbn, 1000k tbc
  [ac3 @ 0x9bf9590]No channel layout specified. The encoder will guess the layout, but it might be incorrect.
  Output #0, avi, to 'test5.avi' :
  Metadata :
  ISFT : Lavf52.64.2
  Stream #0.0 : Video : mpeg4, yuv420p, 720x576, q=2-31, 6000 kb/s, 25 tbn, 25 tbc
  Stream #0.1 : Audio : ac3, 44100 Hz, stereo, s16, 128 kb/s
  Stream mapping :
  Stream #1.0 -> #0.0
  Stream #0.0 -> #0.1
  Press [q] to stop encoding
  frame= 1283 fps= 25 q=2.3 Lsize= 38677kB time=51.32 bitrate=6173.9kbits/s
  video:37755kB audio:846kB global headers:0kB muxing overhead 0.198922%

  If I reduce the command for only capturing audio, then the audio file can be played successfully :

  ffmpeg -f alsa -ac 2 -i hw:3,0 -acodec ac3 -ab 128k test5.avi

  [alsa @ 0x8ede420]Estimating duration from bitrate, this may be inaccurate
  Input #0, alsa, from 'hw:3,0' :
  Duration : N/A, start : 70395.998935, bitrate : N/A
  Stream #0.0 : Audio : pcm_s16le, 44100 Hz, 2 channels, s16, 1411 kb/s
  [ac3 @ 0x8eebac0]No channel layout specified. The encoder will guess the layout, but it might be incorrect.
  Output #0, avi, to 'test5.avi' :
  Metadata :
  ISFT : Lavf52.64.2
  Stream #0.0 : Audio : ac3, 44100 Hz, stereo, s16, 128 kb/s
  Stream mapping :
  Stream #0.0 -> #0.0
  Press [q] to stop encoding
  size= 227kB time=13.62 bitrate= 136.8kbits/s
  video:0kB audio:213kB global headers:0kB muxing overhead 6.902375%

  If I run the command for only video capturing then vlc or ffplay can play the video successfully :

  ffmpeg -f video4linux2 -i /dev/video0 -vcodec mpeg4 -b 12000k -r 25 test5.avi

  [video4linux2 @ 0x91d6420]Estimating duration from bitrate, this may be inaccurate
  Input #0, video4linux2, from '/dev/video0' :
  Duration : N/A, start : 1307112044.025687, bitrate : -2147483 kb/s
  Stream #0.0 : Video : rawvideo, yuyv422, 720x576, -2147483 kb/s, 1000k tbr, 1000k tbn, 1000k tbc
  Output #0, avi, to 'test5.avi' :
  Metadata :
  ISFT : Lavf52.64.2
  Stream #0.0 : Video : mpeg4, yuv420p, 720x576, q=2-31, 12000 kb/s, 25 tbn, 25 tbc
  Stream mapping :
  Stream #0.0 -> #0.0
  Press [q] to stop encoding
  frame= 388 fps= 25 q=2.0 Lsize= 12963kB time=15.52 bitrate=6842.5kbits/s
  video:12949kB audio:0kB global headers:0kB muxing overhead 0.114584%

  Strange behaviour I noticed is that when I tried capturing video and audio, I can not capture the audio afterwards any more,
  unless I unplug the AV350 first.

  The G350 is located at card 3 :

  htpc@htpc-01 :/proc/asound/G350/pcm0c$ more info
  card : 3
  device : 0
  subdevice : 0
  stream : CAPTURE
  id : USB Audio
  name : USB Audio
  subname : subdevice #0
  class : 0
  subclass : 0
  subdevices_count : 1
  subdevices_avail : 1

  The OS is a Linux 2.6.38-8-generic with the Ubuntu Natty Narwhal version

  Any help on how to tackle this issue would be great ....

  Thanks !

• AAC encoder : enforce SF delta in PNS and IS SFs

  17 janvier 2016, par Claudio Freire

  AAC encoder : enforce SF delta in PNS and IS SFs
  Make sure to properly enforce maximum scalefactor delta in PNS
  
  and I/S, not as an absolute range but relative to the previous
  
  and first scalefactor, the latter important since PNS uses an
  
  implicit inicial scalefactor derived from the global gain, and
  
  encoded in a different way, which makes a big difference in the
  
  allowed range.
  

  • [DH] libavcodec/aaccoder.c