M2VDownsizer by Makira

RobK · 18th August 2022, 14:40

Years ago, Metakine Inc., the makers of DVDRemaster for the Mac released the source code for M2VDownsizer under the GPL-2. One can still find it via the Wayback machine.

It still compiles and works. But it will crash when compressing small M2V files with a high lowering factor less than 2. This is probably not too surprising since it was written for compressing m2v video from DVD-9 discs so that they would fit on DVD-5 discs.

Code:

$ M2VDownsizer 1.46 3 47163618 < sample_3840x2160.m2v > sample_test.m2v
M2VDownsizer by Makira.
Using 1.460000 as factor, 47163618 as size and 3 as quality - 2 cpu(s).
Assertion failed: (buf < obuf + BUF_SIZE), function putbits, file mpeg2enc/putbits.c, line 35.
Abort trap: 6

Has anyone updated this code?

P.S. When you run it on the command line, you will see
"M2VDownsizer by Makira"

Is Makira the same Makira on this forum?

Emulgator · 20th August 2022, 20:36

I would resize to 720x480/576 before using that app.
I guess that 3840x2160 was unhandled back then, and still is.

So it would boil down to real reencoding and not thowing away Hi-frequency coeffs as most DVD-9-to-5 apps did.

RobK · 22nd August 2022, 17:11

Yes. It looks like M2VDownsizer is really designed to shrink m2v MPEG-2 video from DVD's. So far, I have had no problems shrinking such video. It is not surprising that Metakine decided to use it in their DVDRemaster product for the Mac.

In my experience so far, with MPEG-2 video encoded at higher resolutions, M2VDownszier may crash depending on the resolution.

18th August 2022, 14:40	#1 \| Link
RobK Registered User Join Date: May 2006 Posts: 11	M2VDownsizer by Makira Years ago, Metakine Inc., the makers of DVDRemaster for the Mac released the source code for M2VDownsizer under the GPL-2. One can still find it via the Wayback machine. It still compiles and works. But it will crash when compressing small M2V files with a high lowering factor less than 2. This is probably not too surprising since it was written for compressing m2v video from DVD-9 discs so that they would fit on DVD-5 discs. Code: $ M2VDownsizer 1.46 3 47163618 < sample_3840x2160.m2v > sample_test.m2v M2VDownsizer by Makira. Using 1.460000 as factor, 47163618 as size and 3 as quality - 2 cpu(s). Assertion failed: (buf < obuf + BUF_SIZE), function putbits, file mpeg2enc/putbits.c, line 35. Abort trap: 6 Has anyone updated this code? P.S. When you run it on the command line, you will see "M2VDownsizer by Makira" Is Makira the same Makira on this forum? Last edited by RobK; 20th August 2022 at 03:00.

20th August 2022, 20:36	#2 \| Link
Emulgator Big Bit Savings Now ! Join Date: Feb 2007 Location: close to the wall Posts: 1,545	I would resize to 720x480/576 before using that app. I guess that 3840x2160 was unhandled back then, and still is. So it would boil down to real reencoding and not thowing away Hi-frequency coeffs as most DVD-9-to-5 apps did. __________________ "To bypass shortcuts and find suffering...is called QUALity" (Die toten Augen von Friedrichshain) "Data reduction ? Yep, Sir. We're that issue working on. Synce invntoin uf lingöage..." Last edited by Emulgator; 20th August 2022 at 20:39.

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22nd August 2022, 17:11	#3 \| Link
RobK Registered User Join Date: May 2006 Posts: 11	Yes. It looks like M2VDownsizer is really designed to shrink m2v MPEG-2 video from DVD's. So far, I have had no problems shrinking such video. It is not surprising that Metakine decided to use it in their DVDRemaster product for the Mac. In my experience so far, with MPEG-2 video encoded at higher resolutions, M2VDownszier may crash depending on the resolution.