Author Topic: Avidemux 2.6.7 pixelates frames using CRF  (Read 3021 times)

UnknownVT

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Avidemux 2.6.7 pixelates frames using CRF
« on: February 25, 2014, 08:57:00 PM »
Hi I am new here, and a relative neophyte when it comes to video -

I have a problem with version 2.6.7 (64-bit) running on my Windows 7 64-bit PC.

I only recently discovered CRF - Constant Rate Factor  - and its advantages in compression -
used it on a .mp4 file that was using very high bit rate to try to reduce it in file size.

I have used Avidemux for some years now and was on 2.6.1 -
but updated it to 2.6.7 -

Setting CRF to 22 I re-compressed the mp4 using Mpeg 4 AVC (X264) -
but I got some pretty bad pixellation -


I have done the same recompression using MediaCoder X64 0.8.28.5588 - and did not get any pixellation.

So I tried older version of Avidemux 2.6.6 and it gave the same pixellation at the same region of the video.

When downgraded to 2.6.1 and using the same settings -
this pixellation went away -
needless to say I am back on version 2.6.1 (64-bit).

Now here's a slight wrinkle -
I get this bad pixellation when playing the recompressed mp4 on WMP - Windows Media Player 12 -
but it is not present when playing on Media Player Classic.

Now I am NOT sure if this pixellation is only for CRF - since that's probably the only setting I tried.

Comments/suggestions please?

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Vincent

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« Last Edit: February 26, 2014, 05:40:35 AM by UnknownVT »

mean

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Re: Avidemux 2.6.7 pixelates frames using CRF
« Reply #1 on: February 26, 2014, 06:32:33 AM »
I dont think it is linked to CRF mode
Encoding using any mode would probably raise the same defect which is IMHO a decoding error, not an encoding error

UnknownVT

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Re: Avidemux 2.6.7 pixelates frames using CRF
« Reply #2 on: February 26, 2014, 07:12:32 AM »
I dont think it is linked to CRF mode
Encoding using any mode would probably raise the same defect which is IMHO a decoding error, not an encoding error

Thank you for the response.

Do you mean error in decoding by Avidemux or by WMP?

I don't see any pixellation when using MediaCoder and the older version Avidemux 2.6.1.

Also it seems that Media Player Classic is able to pay the resultant  "pixellated" recompressed video without the pixellation -
as does my BluRay (media) Player (LG BP320) on my TV using WMP's DLNA server.

So this case may seem a specialized/isolated case?
Although playback of results using Windows Media Player would seem pretty common.

(If the decoding error is in WMP - then perhaps I have to look at the Codec I'm using?)

Thanks,

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Vincent

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