On Wed, 23 Nov 2011 09:27:59 +0100, David Kuehling wrote:
"cenobyte" == cenobyte <[email protected]> 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@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
Feature
VIDEO: [theo] 540x360 0bpp 29.970 fps 0.0 kbps ( 0.0 kbyte/s)
[V] filefmt:44 fourcc:0x6F656874 size:540x360 fps:29.970
ftime:=0.0334
==========================================================================
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
MMX2
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.
Exiting...
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