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.
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 :
"E:\Program Files\Yamb\mp4box.exe" -par 1=64:45 %1
IF [%1]== GOTO END
Replace the path to mp4box as appropriate. Then just drag and drop files to be fixed onto the bat file.
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.
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:
It works without reencoding but patches the values in the h264-stream instead.