[theora] DVD NTSC video plays twice as fast when encoded with libtheora

[Keith Richie]

On Sat, Jun 20, 2009 at 2:37 AM, Jason Self<jason.self at gmail.com> wrote:
>
> On Jun 19, 2009, at 11:23 PM, Keith Richie wrote:
>
>> On Sat, Jun 20, 2009 at 1:59 AM, Jason Self<jason.self at gmail.com>
>> wrote:
>>> On Fri, Jun 19, 2009 at 10:56 PM, Jason Self <jason.self at gmail.com>
>>> wrote:
>>>>
>>>> https://roundup.ffmpeg.org/roundup/ffmpeg/issue1197
>>>>
>>>> I had originally encountered this problem using ffmpeg2theora. I
>>>> switched to ffmpeg proper in an attempt to identify where the
>>>> problem
>>>> was at, and found that the problem persisted. As a result I had
>>>> thought this was a problem with ffmpeg, but the ffmpeg folks seem to
>>>> indicate that this is specific to Theora (too much finger pointing I
>>>> think.) I can confirm that switching codecs does solve the problem,
>>>> though. Anyone care to weigh in? A small section (10MB) of the
>>>> problematic video can be obtained from
>>>> http://shows.bluehome.net/kfp_small.vob.
>>>
>>> One other thing: I can run the DVD through HandBrake (which makes use
>>> of libavcodec and libavformat from the FFmpeg project) using
>>> Theora/Vorbis and it's perfectly fine.
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>>>
>>
>>
>> Works fine for me as well.
>>
>> ffmpeg -i kfp_small.vob -croptop 56 -cropbottom 56  -aspect 2.35 -r
>> 24000:1001 -f yuv4mpegpipe - | sh
>> libtheora-1.1alpha2/examples/encoder_example -v 9 - -o small.ogv
>>
>> ffmpeg -i kfp_small.vob -vn -ac 6 -f wav - | oggenc -R 48000 -C 6 - -
>> o out.ogg
>>
>> oggz-merge -o kfp_small.ogv small.ogv out.ogg
>>
>> Here's a link -
>> http://www.zshare.net/download/616138466a701e2c/
>
> Okay; but you're using ffmpeg to read the original material and then
> piping to other programs... I don't think this can be done with
> ffmpeg2theora.
>
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>


Notice the command line I used -
-r 24000:1001

ffmpeg(2theora) most likely attempts to decode the stream at ~60fps (2
x 29.970).