Can I fix an incorrectly encoded MPEG4 file?

[wiseant]

Hi All

I have some progressive XviD encodes done at 29.97 fps whereas the source was 23.936/24 fps - most of these originated from 352x240 mpeg1 clips

These XviD encodes exhibit this behaviour:
The first 3 frames are good and the next 2 frames are blurry -> GGG BB GGG BB GGG BB

I tried
Telecide(1)
Decimate()

Which removes one of the blurred frames but the other blurred frame still exists - is there a way to "blend the blurry 4th and 5th frames" into one frame so there is no blurriness?

Is there anything I can do to fix this by re-encoding. What Avisynth script would I use or VDub settings?


TIA

[jagabo]

You can try the CDeBlend filter but a video that was blend deinterlaced, converted to VCD, then to Xvid may not deblend very well.

http://avisynth.org/RemovingBlendedFilmFramesOnVcds
http://avisynth.org/mediawiki/C_deblend

[manono]

FixBlend IVTC and now its successor, SRestore, was designed for that (taking a 5 frame telecined and deinterlaced sequence and restoring 4 clean frames), and does a pretty decent job. Both are found in the R_Pack:

http://forum.doom9.org/showthread.php?p=673243#post673243

But as jagabo says your source isn't exactly ideal, as it was designed for DVDs, and not XviDs that have been resized and reencoded a couple of times already

[jagabo]

FixBlend IVTC and now its successor, SRestore, was designed for that (taking a 5 frame telecined and deinterlaced sequence and restoring 4 clean frames), and does a pretty decent job. Both are found in the R_Pack:

http://forum.doom9.org/showthread.php?p=673243#post673243

Thanks manono. I haven't been keeping track of the deblenders.

The OP will also need Donald Graft's Decomb package and the Average() function:

http://neuron2.net/decomb/decombnew.html
https://forum.videohelp.com/topic330377-30.html#1710860

[wiseant]

Thanks jagabo and manono

I'll check these out and post my findings

[wiseant]

hey jagabo and manono

I checked out the forums that you linked to and downloaded these files:

restore24.rar, R_pack.zip, Average_21Oct05.dll, Average_v11.zip, RemoveGrain-1.0.rar, TIVTCv105.zip, masktools-v2.0a35.zip

One version of Average.dll is 12/16/2007, the other is 08/10/2007 [_21Oct05.dll] which one should I use?

This is intense stuff - I decided to put it off to later - what I did do was use Decimate(5) which gave me 23.976 fps and only one blurry frame out of 4 - my logic being that 1/4 [25%] is better than 2/5 [40%] - and the XviD encode that I did looked OK on my TV.

I actually had the same situation with an x264 in a MKV container that I used Lagarith codec for the Decimate(5) then XviD.

BTW I have lots of old 352x240 MPEG1 files - what is the best way to encode to XviD - presuming that they originated as 24 fps film?
And for DVDs that originated from film do I just use Decimate(5) as well?

TIA

[manono]

If I were you I'd use the FixBlendIVTC_v091a found in the "Old" folder. It's now been incorporated into SRestore, but SRestore also includes the former CDeblend and MRestore, and thus requires reading and understanding the doc in order to set it up correctly just for unblending telecined and blend deinterlaced film. FixBlendIVTC does only that and is pretty easy to set up. All the information needed is in the .avs itself.

I think I'd always use the newer version of any of the DLLs.

BTW I have lots of old 352x240 MPEG1 files - what is the best way to encode to XviD - presuming that they originated as 24 fps film?

If they've already been deinterlaced, then FixBlendIVTC. If not, then IVTC them. Read the docs that come with DGMPEGDec for information about performing a full IVTC if you don't know how to set up an AviSynth script and apply IVTC.

And for DVDs that originated from film do I just use Decimate(5) as well?

No. If they are soft telecined, make the D2V using Force Film and you already have progressive 23.976fps. If hard telecined make the D2V using Honor Pulldown Flags in DGIndex and apply a full IVTC (The old Telecide().Decimate(5) one-two punch).

[wiseant]

Thanks manono

Looks a lot easier to use this FiXBlendIVTC . . .

BTW, I thought a 352x240 MPEG1 can never be interlaced - am I missing something here?

Also, if I have a DVD that originated from 24 fps film and want to encode to MPEG4 or X264, then I would use the "D2V using Honor Pulldown Flags in DGIndex and apply a full IVTC (The old Telecide().Decimate(5) one-two punch)." ?

TIA

[jagabo]

NTSC VCD isn't interlaced. A film source will either have every 5th frame a duplicate (1, 2, 3, 4, 4, 5, 6, 7, 8, 8...) or you will see blend deinterlaced frames in 2 of every 5 frames like your earlier sample. The former can simply be decimated to 24 fps. The later needs FixBlendIVTC.

As manono said, if a DVD source encoded progressive with 3:2 pulldown flags (these tell the DVD player how to produce 59.94 fields from the 24 fps frames) you can use DgIndex with Force Film to retain those progressive 24 fps frames. If it has hard pulldown you need to IVTC.

[manono]

NTSC VCD isn't interlaced.

Oh, it isn't? Learn something new every day. I've never seen a VCD, but I just ordered 2 the other day as the films I want aren't out on DVD, so within a week I'll have my first look. Thanks for the correction.

[wiseant]

Hi jagabo and manono

Thanks again for your help.
I did try the FixBlendIVTC version: v0.9b - 20.12.2006 [not _v091a]

It worked! my fps encoding speed was cut in 1/2 but no big deal - also, I didn't run LimitedSharpen() [didn't have it] but I did try LimitedSharpenFaster() but I did not like the result - so I removed it - and I also used Deblock() 'cause of the blockiness I noticed on the clip

I just compared the two clips on my TV, the one with FixBlendIVTC is definitely better looking than the one with just Decimate(5)

Thanks again.