[MEncoder-users] Accuracy of the -endpos option

[belcampo]

Josef Wolf wrote:
> On Mon, Jun 28, 2010 at 10:32:24PM +0200, belcampo wrote:
>> Josef Wolf wrote:
>>> On Mon, Jun 28, 2010 at 04:38:29PM +0200, belcampo wrote:
>>>> Josef Wolf wrote:
>>>>> Hello,
>>>>>
>>>>> I have troubles with the accuracy of the -endpos option. Most of the time,
>>>>> I get about 40 to 50 frames too much. When I adjust the value to get the
>>>>> correct end position, then audio ends about 2 seconds too early.
>>>> With ffmpeg -vframes ### you can exactly say how many frames you want.
>>>> The problem with -endpos or -t when using ffmpeg, it uses recording
>>>> duration, NOT video- or audio-duration but the smallest of them.
>>> Hmmm... Does mencoder have a counterpart to -vframes? I have gone a long way
>>> to optimize the codec settings for mencoder and would like to avoid to start
>> >from scratch when moving to ffmpeg...
>> If you post your command line settings, maybe it's easy translated
>> to ffmpeg, or use the solution explained further.
> 
> Sure, I can post them:
> 
>   mencoder \
>   -ss 00:00:01.880 -endpos 241.92 \
>   -vf yadif=0,crop=704:560:8:8,softskip,harddup \
>   -oac mp3lame -lameopts preset=medium -passlogfile \
>   -ovc x264 -x264encopts \
>   bitrate=800:pass=2:subq=7:frameref=15:me=umh:partitions=all:8x8dct:direct_pred=auto:me_range=64:trellis=2:bframes=5:weight_b:threads=auto:nr=1000:b_pyramid=normal:turbo=2 \
>   -passlogfile x264-800/2010-05-08-Tanz-Jan-3-Tanz.avi.log \
>   -o x264-800/2010-05-08-Tanz-Jan-3-Tanz.avi \
>   2010-05-09-Tanz-Jan008.avi
> 
> Whatever I tried, I get much bigger files with very bad quality from ffmpeg.
All those -ovc x264 -x264encopts ... and there ffmpeg equivalents, they 
are the same, mencoder and ffmpeg use exactly the same x264 libraries, 
so there can't be any difference in that part.
http://rob.opendot.cl/index.php/useful-stuff/x264-to-ffmpeg-option-mapping/

Could you provide a sample, an upload somewhere, of the source-file ?
Some general thoughts, not knowing what kind of source yor dealing with.
me_range=64 where mewiki.project357.com/wiki/X264_Settings says
merange

Default: 16

merange controls the max range of the motion search in pixels. For hex 
and dia, the range is clamped to 4-16, with a default of 16. For umh and 
esa, it can be increased beyond the default 16 to allow for a 
wider-range motion search, which is useful on HD footage and for 
high-motion footage. Note that for umh, esa, and tesa, increasing 
merange will significantly slow down encoding.

frameref=15
Looks rather/very high to me
>
<snip>


> So demuxing, encoding/snipping, and muxing afterwards should also work fine?
> Last time I tried, mencoder refused to process a video stream without audio or
> an audio stream without video.
I'm used to use more then 1 application, I try to pick 'the best' for a 
given task. Maybe it's not your piece of cake.