Anamorphic video

[Chengbin]

I'm lost about the anamorphic video. It seems to "morph" the video into a different aspect ratio than its own when you play it (I've seen 16:9 anamorphic videos that have a resolution of 720x480). How do you encode that. Does it have its benefits quality wise? For quality, is it better to use anamorphic encoding or a similar MOD16 resolution (like 704x400 for 16:9).

BTW, does MOD32 give better quality than MOD16?

[J_Darnley]

You encode it either by telling the encoder that the video should be stretched, using x264 set the --sar option (that is the Sample Aspect Ratio), or by telling the muxer that the video should be stretched, using mkvmerge set the --display-dimensions option.

As for video dimensions being multiples of numbers > 16, it does not affect encoding at all. Except for interlaced, I can't say about that.

[Esurnir]

MOD32 got absolutely no impact on anything

dvd are encoded in 720*480 for ntsc, 720*576 for pal. The reason it's that way is that some drunk engineer at ITU or SMPTE found it would be fun to create digitizing equipement for transforming analogue ntsc waveform into digital signal (to transport on SDI serial link) that would result in non square pixel. To make hardware maker happy, DVD must have material that could be decoded on 720*480.

Anamoprhic video exist for the sole reason that most source are encoded that way.

As for quality, if your going to watch a movie on your hdtv or computer screen in full screen, the less you resize the movie the better the quality. Unless you use an awesome upscaling algorithm (NNEDI?) your better off not stretching the movie horizontaly to make it bigger (as a tv would display it). And if your only playing the movie on a computer in full screen, quality wise, anamoprhic encoding will be better than squizzing the movie verticaly, even if at "normal playback (unzoomed)" size it give the greatest quality in my opinion.

[Esurnir]

You encode it either by telling the encoder that the video should be stretched, using x264 set the --sar option (that is the Sample Aspect Ratio), or by telling the muxer that the video should be stretched, using mkvmerge set the --display-dimensions option.

Sometimes both, the DXVA filter of mpc-hc in my case doesn't care about the muxer info and solely care about the bitstream.

[Chengbin]

So you guys are saying I should use anamorphic encoding?

I'm viewing this on my Archos 5, 5'' screen, 800x480.

[Esurnir]

So you guys are saying I should use anamorphic encoding?

I'm viewing this on my Archos 5, 5'' screen, 800x480.

Try it on a short sequence (Trim(1000,2000)) with --sar in the commandline and I think there is a par settings somewhere in mp4box.

However it`s far from sure that the archos does a resize. Some software may not do any resize and assume every video is square pixel encoded.

[Chengbin]

Try it on a short sequence (Trim(1000,2000)) with --sar in the commandline and I think there is a par settings somewhere in mp4box.

However it`s far from sure that the archos does a resize. Some software may not do any resize and assume every video is square pixel encoded.

Yes, the Archos supports anamorphic videos. They're very video oriented players, but unforunately still does not support H.264 high profile.

[Esurnir]

Try with anamorphic encoding then try with a good upscaler (Lanczos4Resize() LanczosResize, not NNEDI since it's limited to power of 2 resizing).

Obviously the anamorphic encoded video will be smaller. But the Resized video may look sharper. Compare it on your archos and see which one is best. (does archos support mkv ? if so it'll make your muxing alot easier)

[Chengbin]

Try with anamorphic encoding then try with a good upscaler (Lanczos4Resize() LanczosResize, not NNEDI since it's limited to power of 2 resizing).

Obviously the anamorphic encoded video will be smaller. But the Resized video may look sharper. Compare it on your archos and see which one is best. (does archos support mkv ? if so it'll make your muxing alot easier)

No, unforunately. It doesn't support MKV. It might in the future. But that was also a big letdown.

I'm not sure what you mean by upscaler. There are no upscalers on a PMP.

I'll test it when I get home. I'm at school now (business class, having some free time after finishing all the work)

[nm]

I'm not sure what you mean by upscaler. There are no upscalers on a PMP.
He means scaling to the native square pixel resolution before encoding to avoid the possibly inferior scaling of Archos.

[Esurnir]

The archos in the end will stretch horizontaly and do some upscaling to make the video fit the screen. Maybe or maybe not the hardware upscaling of the archos will be vastly inferior as what you could do in avisynth