New OpenWrt Release: stable 2011-11-13

cenobyte at cenobyte at
Wed Nov 23 14:37:13 EST 2011

 On Wed, 23 Nov 2011 09:27:59 +0100, David Kuehling wrote:
>>>>>> "cenobyte" == cenobyte  <cenobyte at> writes:
>> I forgot to mention a tip I have found useful for making ogv videos. 
>> I
>> use ffmpeg2theora to convert clips I save from Youtube or what have
>> you to Nano size. I pass along the -x 320 -y 240 options as well as
>> the -sameq. Make sure not to use the ffmpeg syntax of -s 320x240, 
>> that
>> won't get you far.  I have been experimenting with ripped DVD's and
>> have converted one to size, but it is off sync (it was encoded off
>> sync, not played back off sync). I have tried passing the --sync
>> option along but so far no luck, the program will not begin
>> encoding.
> ffmpeg2theora seems to have some problems with syncing against mpeg
> streams.  As a workaround, you could use mencoder (i.e. the one that
> ships with mplayer) to first transcode to a losslessly compressed 
> .avi
> file, then feed that .avi into ffmpeg2theora.  Mencoder's sync 
> handling
> is superb.  The resulting .avi file will have no per-frame timestamps 
> so
> ffmpeg2theora conversion won't introduce audio desync.
> mencoder -oac pcm -ovc lavc -lavcopts vcodec=huffyuv:vstrict=-1 \
>          -o intermediate.avi
> (maybe you'd want mencoder to already do the scaling:
> -vf scale=320:240)
> cheers,
> David

 This is what I get when trying to do as you said:

 cenobyte at cenobyte-901:~$ mencoder Ferngully_540x360.ogv -o 
 intermediate.avi -ovc lavc -oac pcm -lavcopts vcodec=huffyuv:vstrict=-1 
 -vf scale=320:240
 MEncoder 1.0rc4-4.5.2 (C) 2000-2010 MPlayer Team
 success: format: 0  data: 0x0 - 0x150ce3aa
 libavformat file format detected.
 [theora @ 0x9f2d9d0]7 bits left in packet 82
 [lavf] stream 0: video (theora), -vid 0
 [lavf] stream 1: audio (vorbis), -aid 0, -alang en, Title 1 - Main 
 VIDEO:  [theo]  540x360  0bpp  29.970 fps    0.0 kbps ( 0.0 kbyte/s)
 [V] filefmt:44  fourcc:0x6F656874  size:540x360  fps:29.970  
 Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
 AUDIO: 44100 Hz, 2 ch, s16le, 128.0 kbit/9.07% (ratio: 16000->176400)
 Selected audio codec: [ffvorbis] afm: ffmpeg (FFmpeg Vorbis)
 Opening video filter: [expand osd=1]
 Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
 Opening video filter: [scale w=320 h=240]
 Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
 [theora @ 0x9f906c0]7 bits left in packet 82
 Selected video codec: [fftheora] vfm: ffmpeg (FFmpeg Theora)
 Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
 [swscaler @ 0xa1e9ee0]BICUBIC scaler, from yuv420p to yuv420p using 
 videocodec: libavcodec (320x240 fourcc=55594648 [HFYU])
 [huffyuv @ 0x9f8fe30]Error: YV12 is not supported by huffyuv; use 
 vcodec=ffvhuff or format=422p
 Could not open codec.
 FATAL: Cannot initialize video driver.
 Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
 videocodec: libavcodec (320x240 fourcc=55594648 [HFYU])
 Could not open codec.
 FATAL: Cannot initialize video driver.


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