Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I just bought a Samsung Camcorder (SMX-F30BP). It has the ability to capture in standard Aspect Ratio (I guess 4:3) or in 16:9 format. The problem is that the mp4 (H.264) file generated is always regarded as a 4:3 format in any player I tried (media player, MPlayer, VLC, etc.), despite the fact that the frames are actually 16:9. Only by manually setting the Aspect Ratio to 16:9 in the player, I get the movie right. Does someone has a clue on what is going on? Is it a bug in the cam software? Is there something I can do? Thank you for your answers.

share|improve this question
    
VLC allows you to change the AR on-the-fly ... mine is an old version and uses 'A' as the AR-change-hotkey. keep pressing to cycle through the options. other decent players will let you change it while playing too. but for permanent change you want the article linked below. –  quack quixote Oct 28 '09 at 11:43

3 Answers 3

up vote 1 down vote accepted

There is simple way to correct spect ratio without re-encoding.

The Samsung MX20 does not tag its 16:9 files with the correct DAR. To fix this without a re-encode use Yamb (or mp4box), setting the aspect ratio to 64:45 for PAL videos. As in this test video of a round spray can top shot from above. No other editing was done before uploading to YouTube. Alternatively, install mp4box and use this batch file :

@ECHO OFF

:LOOP

"E:\Program Files\Yamb\mp4box.exe" -par 1=64:45 %1

SHIFT

IF [%1]==[] GOTO END

GOTO LOOP

:END

Replace the path to mp4box as appropriate. Then just drag and drop files to be fixed onto the bat file.

Source: http://www.youtube.com/watch?v=rg4pc2rQ9Rw

share|improve this answer
    
That's what I just resolved to do! Unfortunately I have to process all the files however. Thanks, your answer is correct. By the way, I use the option -par 1=16:11 for PAL, as suggested by Yamb, not 64:45. –  Overflow Mar 4 '10 at 15:23
    
I investigated a little deeper and found out that actually 64:45 is the correct PAR for the format 720x576 to obtain exactly 16:9 AR. –  Overflow Mar 5 '10 at 15:57

You can modify the aspect ratio without re-encoding.

EDIT : For MP4 files see this article:
Change Aspect Ratio of .mp4 without re-encoding

See MPEG4 Modifier

Modifies MPEG-4 ASP videos (XviD, DivX) without re-encoding (change aspect ratio, edit userdata, remove or add packed bitstream, and change interlaced field order). It can also show information about the video such as the amount of I/P/S/B-VOPs used, whether or not QPel/GMC were used, etc. The video must be in an AVI container. More information can be found in this thread. There's also a command line version sharing most of the same features.

image

share|improve this answer
    
Nice. I knew there had to be a way. Still, weird that the camera itself doesn't already embed that information. –  Joey Oct 28 '09 at 10:37
    
Sorry, but the clip format is MP4, not AVI, so I should have to convert it first, then modify the AR. @Johannes Rössel, why did you remove your previous answer? I think it was correct and I was going to "accept" it –  Overflow Oct 28 '09 at 10:53
    
See the article I edited into my answer. –  harrymc Oct 28 '09 at 11:31

The MPEG4-Modifier does only work for DIVX encoded files. For H264-encoded videos you could try to use the H264 Apect Ratio Modifier (H264ARM) from this thread:

http://forum.videohelp.com/threads/316259-Can-I-change-the-pixel-aspect-ratio-in-an-x264-AVI-without-reencoding

It works without reencoding but patches the values in the h264-stream instead.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.