changing Aspect Ratio of AVC streams in .mp4

[hhanh]

Well ... I wrote a program to change the p/ar in the mp4 file.

--h

[Selur]

@hhanh: If it works, it would be nice if you could share it with the community

Cu Selur

[hhanh]

Sure. Here it is.

[Selur]

mods plz authorize

[bond]

splitted and authorized

hhanh, can you plz tell us the correct commandline options to use to change the ar, thanks

[hhanh]

Usage: ARChange.exe -i mp4-file -t track-no [-a width:height]

The track-no is the video track #. You can get it with mp4info. For mp4 files made with Nero Recode, I think it's always 3.

To display the current A/R:
ARChange -i test.mp4 -t 3

To change it to 8:9
ARChange -i test.mp4 -t 3 -a 8:9

A 4:3 DVD source has a PAR of 8:9 because it is 4/3 * 480/720
For a 16:9 DVD source, it's 32:27.

--h

[Selur]

thx for this tool

Cu Selur

[SeeMoreDigital]

Can somebody make a GUI for this tool?

Maybe hhanh and Moitah can get their heads together and add this functionality to MPEG4 Modifier

What do you say guys?


Cheers

[Sharktooth]

MPEG4Modifier lacks the MP4 container support.
Once (and if) it will be added MPEG4Modifier will be the definitive tool

[SeeMoreDigital]

Originally posted by hhanh
Usage: ARChange.exe -i mp4-file -t track-no [-a width:height]

The track-no is the video track #. You can get it with mp4info. For mp4 files made with Nero Recode, I think it's always 3.

To display the current A/R:
ARChange -i test.mp4 -t 3

To change it to 8:9
ARChange -i test.mp4 -t 3 -a 8:9

A 4:3 DVD source has a PAR of 8:9 because it is 4/3 * 480/720
For a 16:9 DVD source, it's 32:27.

And here are the settings you'll need for both PAL and NTSC 4:3 and 16:9 DAR (which are based on PAR): -

Required AR             Custom DAR(PAR) Setting   
4:3 PAL                 64:60 (or 16:15)
16:9 PAL                64:45  
4:3 NTSC                64:72 (or 8:9)
16:9 NTSC               64:54 (or 32:27)

Cheers

[hhanh]

I don't know, man. I'm working on a mp4 splitter/muxer at the moment. Besides GUIs were never my forte.

--h

[bond]

hhanh, i now found the time to test this tool with the following commandline:

ARChange -i "C:\path to\mymp4.mp4" -t 201 -a 16:11

used 16:11 because thats the value defined in mpeg-4 for 16:9 pal

i also tested different .mp4 files (different ASP video streams, created/muxed with nero, mp4ui and mp4box) and different -t/-a settings, but i always got the following error message:

Assertion failed: !"Unexpected EOF", file ARChange.cpp, line 368

abnormal program termination

any idea what went wrong?

btw is it supposed to work with AVC or ASP video streams?

with avc .mp4 files (created with ateme/nero), i get the following error message:

Assertion failed: fAR || !"A/R not present", file ARChange.cpp, line 567

abnormal program termination

[Mosu]

I guess it's for ASP only. I'm trying to implement AR extraction for AVC at the moment, and it totally sucks compared to ASP. WAY more complicated.

But if it CAN change the AR for AVC then I'd really like to see the source code for that

[SeeMoreDigital]

Originally posted by bond
any idea what went wrong?

I've got a feeling this tool might currently only work with DAR values, such as the ones I posted.

Did you try any of them?


Cheers

[bond]

same results with the DAR values

[SeeMoreDigital]

Originally posted by bond
same results with the DAR values

Oh well... I thought it may have followed what Moitah posted about DAR here: -

http://forum.doom9.org/showthread.ph...784#post561784

But if it don't... it don't!


Cheers

[RanmaSaotome]

Just like to say i tested your program on a Nero Digital AVC file & it worked fine. It was an avs file encoded using Recode2 in the max definition AVC profile.

C:\Encode>mp4box -info video.mp4
* Movie Info *
Timescale 1000 - Duration 00:25:41.164
Fragmented File no - 3 tracks
File Brand avc1 - version 0
File has root IOD
Scene PL 1 - Graphics PL 254 - OD PL 254 - Visual PL 255 - Audio PL 0

Track # 1 Info - TrackID 1 - TimeScale 1000 - Duration 00:00:01.000
Track is present in Root OD
Media Type "odsm" - Media Sub Type "MPEG" - 1 samples
MPEG-4 Config: ObjectDescriptor Stream - ObjectTypeIndication 1
Self-synchronized

Track # 2 Info - TrackID 2 - TimeScale 1000 - Duration 00:00:01.000
Track is present in Root OD
Media Type "sdsm" - Media Sub Type "MPEG" - 1 samples
MPEG-4 Config: SceneDescription Stream - ObjectTypeIndication 1
Synchronized on stream 1

Track # 3 Info - TrackID 3 - TimeScale 24000 - Duration 00:25:41.164
Media Type "vide" - Media Sub Type "avc1" - 36951 samples
Unknown track type


C:\Encode>ARChange -i video.mp4 -t 3
Current A/R = 1:1

C:\Encode>ARChange -i video.mp4 -t 3 -a 32:27
Current A/R = 1:1

C:\Encode>ARChange -i video1.mp4 -t 3
Current A/R = 32:27

Amazing how this tool just popped up right when I needed it thanks.

**Edit

Both nero show time & wmp now recogize the video as being 16:9

It was encoded at a res of 600x400.

[SeeMoreDigital]

Blimey...

I wasn't expecting this tool to work with Mpeg4/AVC in MP4 files. Especially from a codec as advanced as Nero's!


Nice one!

[bond]

hm the following findings:

1) the tool only seems to work with .mp4 files where the avc stream already contains an ar value (which was not the case with the nero samples i had)

2) i created an avc stream with x264 and imported to .mp4 with mp4creator: seems as if x264 sets an ar in the stream when encoding automatically (in my case 64:45 for an encoded PAL 16:9 DVD source)

still i dont really get the tool to work 100% correctly:
- i run the tool on the file changing the ar
- a seperate x.mp4.out file get created (with the same filename as the input.mp4), which seems to be a valid .mp4 file
- nero and moonlight (only when you force overlay mixer2 in the graph) plays the file with the newly set ar
- still when i run the ar tool again on the renamed new x.mp4 it doesnt work "Invalid SAR value"

[EthanoliX]

Same problem here. The only difference is, the created file is not shown with the corrected ar.