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Subject: Re: [OMPI users] Open MPI instructional videos
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-06-04 13:45:32


Thanks for the tip!

I downloaded and tried the qt_tools but all conversions that I did to
the MP4 format looked absolutely horrid -- the resulting videos had
"jagged" images and all kinds of weird artifacts that would appear and
disappear. The slides were quite readable, but they just looked "bad".

Does anyone else have any suggestions? Perhaps I need to record them
differently so that they can be converted to both .mov and .mp4 nicely
at the end...?

On Jun 4, 2008, at 9:03 AM, Scott Atchley wrote:

> Jeff,
>
> If I remember correctly, Microsoft dropped support for .AVI 3-4 years
> ago so it can no longer be played by their media player. It is also
> not native to QT, so you will have to download a plugin (I have it
> somewhere if you want me to look for it).
>
> I do not know if there is a container format that all players are
> happy with. My guess would be that MP4 would be the closest.
>
> You can convert .mov to .mp4 with a free command-line app, qt_export,
> which is part of qt_tools. It uses the QT libraries and can transcode
> to a number of video and audio formats (including AVI if you have the
> QT plugin).
>
> Scott
>
> On Jun 4, 2008, at 8:31 AM, Jeff Squyres wrote:
>
>> FWIW: I tried the http://adi.loris.tv/ompi-optimized.avi URL on my
>> Mac
>> and got redirected to the Quicktime plugin page. I had no idea which
>> plugin would make it play AVI files, so I skipped it. I tried the
>> URL
>> on a Windows machine and Windows Media Player (i.e., what came up by
>> default) seemed to play the audio just fine, but it couldn't find a
>> video codec. Here's the error message that it showed:
>>
>> The codec you are missing is not available for download from this
>> site.
>> You might be able to find it on another site by searching the Web
>> for
>> "FMP4" (this is the WaveFormat or FourCC identifier of the codec).
>>
>> That being said, if we can get a format that works nicely on multiple
>> platforms / is convenient for users, it would be great if you could
>> convert them for me -- thanks!
>>
>> The entire web site is in a SVN repository (our mirrors just run "svn
>> up" every night): http://svn.open-mpi.org/svn/ompi-www/trunk. The
>> videos are under /video (the same directory structure of the web
>> site).
>>
>>
>> On Jun 4, 2008, at 6:13 AM, Adrian Knoth wrote:
>>
>>> On Wed, Jun 04, 2008 at 11:19:48AM +0200, Adrian Knoth wrote:
>>>
>>>> People usually recommend ffmpegX for OSX. You might give it a whirl
>>>> to
>>>> transcode your mov to something else, let's say H.264 in an AVI
>>>> container. (MP4/AVC, DivX, xvid, there are so many names for it)
>>>
>>> I've checked your files, they're quite good. They are already H.264
>>> and
>>> AAC (advanced audio coding), the only thing wrong is the mov
>>> container.
>>>
>>> It's easy to repack this to avi:
>>>
>>> $ mencoder input.mov -ovc copy -oac copy -o output.avi
>>>
>>> I've tested it with openib-btl-tuning:
>>>
>>> adi_at_chopin:/tmp$ ls -l openib-btl-tuning-v1.2.mov
>>> -rw-r--r-- 1 adi adi 16249094 Jun 4 11:24 openib-btl-tuning-
>>> v1.2.mov
>>>
>>> adi_at_chopin:/tmp$ ls -l ompi-test.avi
>>> -rw-r--r-- 1 adi adi 15964104 Jun 4 11:26 ompi-test.avi
>>>
>>> (you can download it here: <http://adi.loris.tv/ompi-test.avi>)
>>>
>>> On the other hand, the files are way too large. The video doesn't
>>> contain much inter-frame correlation, so it's a good idea to give
>>> the
>>> encoder some hints:
>>>
>>> adi_at_chopin:/tmp$ ls -l test*.avi
>>> -rw-r--r-- 1 adi adi 36171648 Jun 4 11:47 test.avi
>>> -rw-r--r-- 1 adi adi 35323842 Jun 4 11:58 testx264.avi
>>>
>>> (from approx. 160MB to 35MB). The first one is MPEG4 with an MP3
>>> audio
>>> stream, the second is H.264. Both video encoders were forced to
>>> 100kbit/s
>>> and keyframes every 300 frames (not for x264):
>>>
>>> $ mencoder input.mov -oac mp3lame -ovc lavc -lavcopts \
>>> vbitrate=100:keyint=300 -o output.avi
>>>
>>> For testing purposes, try http://adi.loris.tv/ompi-optimized.avi
>>>
>>> I'd like to hear if these files, especially the last one, are
>>> working for
>>> other users.
>>>
>>> If so, I'd take care to convert the movs to avi, probably MPEG4.
>>>
>>> (in that case: Jeff, you could probably give me all files in an
>>> archive
>>> or point to a direct download link, so I don't have to click through
>>> the
>>> website but just fire up the encoder in the for loop)
>>>
>>> --
>>> Cluster and Metacomputing Working Group
>>> Friedrich-Schiller-Universität Jena, Germany
>>>
>>> private: http://adi.thur.de
>>> _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
>> --
>> Jeff Squyres
>> Cisco Systems
>>
>>
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>
>
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-- 
Jeff Squyres
Cisco Systems