What is the best video format for least VLC CPU time usage?

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Mel_3
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What is the best video format for least VLC CPU time usage?

Postby Mel_3 » 04 Jun 2011 01:32

Status:
- Running VLC on old Pentium-4 1.8 Ghz PC with XP-Pro w/1GB Ram
- Two other apps are running at the same time.
- VLC struggles to playback the video even with just Windows Task Manager open

- Video is MP4 converted from AVI
- Converted files with both Handbrake and dotNetFFMPEG

- Handbrake files are 720x480 29.97 fps & Gspot reports 617kbs

- dotNetFFMPEG files are 640x480 29.97 fps & Gspot reports 1,373bps

The Question: If we want VLC to make smallest demands on CPU - what would be the ideal file format & specs ?

We can convert the original AVI files to any format & specs if we just knew the most efficient for vlc to playback.
Thanks for any help.

Lotesdelere
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Re: What is the best video format for least VLC CPU time usa

Postby Lotesdelere » 04 Jun 2011 11:04

Assuming you are encoding to H.264 using x264, then you can use the 'FastDecode' tune setting but be aware that it will produce a file about 20% larger than with optimized settings:
Tools -> Preferences (Show settings=ALL) -> Input/Codecs -> Video codecs -> x264
then at the bottom of the right panel "Tune the setting for a particular type of source or situation" -> set it to FastDecode.

Mel_3
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Re: What is the best video format for least VLC CPU time usa

Postby Mel_3 » 04 Jun 2011 14:07

- "Assuming you are encoding to H.264 using x264"

.. I'm using VLC 1.1.9
.. I'm using the VLC default profile Video - H.264 + AAC (MP4)
.. The VLC profile it tells me it is using MP4/MOV Encapsulation and H.264 Codec
.. I don't see any reference to X264

1 - Does VLC come with and use X264 ?
2 - Does this profile use X264?
3 - I see I can download x264 from cnet... should I?

4 - VLC Convert/Save with Profile=Video-H.264+AAC(MP4) produces file with end cut off... how to fix this?
5 - I setup Fast Decode as instructed but is Profile=Video-H.264+AAC(MP4) using it or must I add X264 somehow?

Thanks for the help with this.

VLC_help
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Re: What is the best video format for least VLC CPU time usa

Postby VLC_help » 04 Jun 2011 14:11

MPEG-4 ASP encoder (e.g. Xvid) and decoder might be better option for old computer.

1. Yes.
2. Yes.
3. No. VLC has everything build-in.
4. How much off?
5. It should use it.

Mel_3
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Re: What is the best video format for least VLC CPU time usa

Postby Mel_3 » 04 Jun 2011 16:30

Thanks VLC_help! Really appreciate the help!!!

- Using the Default VLC Profile... Video - H.264 + AAC (MP4) ...to convert the original AVI to an MP4 ...cuts off the last 1.621 seconds

- Modifying this profile to Bitrate=800kbs and Scale=0 fixes the problem! (woops! also need to change profile video codec from h264 to mpeg4)

Default VLC Profile:
:sout=#transcode{vcodec=h264,vb=0,scale=0,acodec=mp4a,ab=128,channels=2,samplerate=44100}:file{dst=C:\\Documents and Settings\\All Users\\Documents\\My Videos\\video1OrigProf.mp4} :no-sout-rtp-sap :no-sout-standard-sap :ttl=1 :sout-keep
If this is a short tutorial clip... or whatever... this is not good.

Modified VLC Profile (bitrate=800kbs, scale=1):
:sout=#transcode{vcodec=mp4v,vb=800,scale=1,acodec=mp4a,ab=128,channels=2,samplerate=44100}:file{dst=C:\\Documents and Settings\\All Users\\Documents\\My Videos\\video1mod-1prof.mp4} :no-sout-rtp-sap :no-sout-standard-sap :ttl=1 :sout-keep

If you look at the transcoded output file with Gspot it shows the length difference...

... VLC default profile Video - H.264 + AAC (MP4) - Len=34.899 seconds
... Profile Mod to kbs=800 and scale=1 yeilds Len=36.52 seconds

1 - Any idea why this is occurring?
fyi - It seems setting the bit rate is what does it... (also need to change profile video codec to mpeg4)
... leave bitrate=0 with scale=1 and no workie...
... but bitrate=800kbs and sale=0 works

2 - I've seen other post with this problem. If setting the bitrate is an OK patch/fix I wonder I should post it under it's own header so others can find it easily until the dev team gets around to a better fix?

3 - Finally, the Fast Decode option doesn't help VLC playback on a Pent-4, 1.8Ghz XP-Pro machine with 1GB ram. Still requires 7-%-80% of cpu. For this case we can transcode or render the files to any decent format to get them to run on the Pent-4 machines... else we have to toss a bunch of PC's and wipe out the budget! Transcoding to WMV still demands 70%-80% cpu time to play back... any other format we should consider?

Thanks again for the help.

Mel_3
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Re: What is the best video format for least VLC CPU time usa

Postby Mel_3 » 04 Jun 2011 19:44

Correction: Upon further testing even this setup is cutting off the last of converted/transcoded videos.
Example:
Original AVI length = 41.242 seconds
Converted MP4 length = 40.974 seconds

This .268 seconds may not seem like much..
... but when the video is a short tutorial or other narrative...
... cutting off the last word or two is not good.

Anybody have any ideas about how to fix this?

Thanks.

VLC_help
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Re: What is the best video format for least VLC CPU time usa

Postby VLC_help » 05 Jun 2011 13:17

VLC 1.2.0 shouldn't cut that much. But for VLC 1.1.x there isn't any good solution.


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