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View Full Version : Which is smaller: mp4 or m4v?




The Valeyard
Jun 17, 2009, 04:54 AM
I am converting all my available Doctor Who episodes for use on my iPod and I used DVD2Pod to convert them to a small video (dimension-wise) and it makes an mp4. I thought that maybe m4vs may be smaller (file size-wise) so that I can fit them onto my 8GB iPod Nano 4G. Does anyone know which is smaller?



spinnerlys
Jun 17, 2009, 05:06 AM
Both file suffixes are just containers for MPEG-4 / H264 encoded video and audio, so there won't be much difference, if at all.
But beware, that the .m4v container is able to handle an .ac3 stream better, if you choose to include that instead of using the MP3 codec.

Why don't you make a comparison and see which file is smaller, by converting an episode with the same settings, just different containers.

The Valeyard
Jun 17, 2009, 06:02 AM
Also, what dimensions would you recommend for the iPod Nano 4G Chromatic to reduce the file size but not make it go pixelated on the screen?

macuser154
Jun 17, 2009, 06:07 AM
Wikipedia says that the 4G's screen is 320x240 horizontally.

The Valeyard
Jun 17, 2009, 06:13 AM
Both file suffixes are just containers for MPEG-4 / H264 encoded video and audio, so there won't be much difference, if at all.
But beware, that the .m4v container is able to handle an .ac3 stream better, if you choose to include that instead of using the MP3 codec.

Why don't you make a comparison and see which file is smaller, by converting an episode with the same settings, just different containers.
Little or no change in file size? m4v +99.7MB. Quite a lot bigger. And MPEG Streamclip takes a lot less time to convert to mp4.

The Valeyard
Jun 17, 2009, 06:22 AM
Do you have any suggestions on how I can bring down the file size?

spinnerlys
Jun 17, 2009, 06:33 AM
Little or no change in file size? m4v +99.7MB. Quite a lot bigger. And MPEG Streamclip takes a lot less time to convert to mp4.

Are you sure, you have used the exact same settings?
Same resolution, same frame rate, same codec for video and audio, ....?

Otherwise I can't understand the difference, as .m4v and -mp4 are just containers, and not codecs itself.
Even some quick research does not explain the discrepancy.


On bringing down the file size: use a smaller resolution, more compression, use a 2-pass encoding. I mean a Nano's display is so small, you won't need that much detail, will you?

The Valeyard
Jun 17, 2009, 07:09 AM
Are you sure, you have used the exact same settings?
Same resolution, same frame rate, same codec for video and audio, ....?

Otherwise I can't understand the difference, as .m4v and -mp4 are just containers, and not codecs itself.
Even some quick research does not explain the discrepancy.


On bringing down the file size: use a smaller resolution, more compression, use a 2-pass encoding. I mean a Nano's display is so small, you won't need that much detail, will you?
What's 2-pass encoding? And does anyone know how to set the release date on TV shows?

spinnerlys
Jun 17, 2009, 09:52 AM
2-pass encoding is for better image quality.
During the first pass the image/picture is analyzed, and in the second pass all the analyzation will be put to the real encoding of the video.

With that method you avoid the artifacts you see sometimes, when a fast movement occurs.

The Valeyard
Jun 19, 2009, 02:40 AM
Can you do that in MPEG Streamclip?