Determine best bitrate for a given resolution

[cd090580]

Hi,

I received a MP4 player with video support. The native screen (2") resolution is 220*176 and I will resize my videos to that resolution.

So I'd like to put some music videos on it but is there a way to determine the best average bitrate for a given resolution ?

Thanks

[yoda313]

Unfortunately there is no true hard and fast rule for any of this. It is very subjective.

All i can say is that generally the smaller the resolution the less bitrate you need. Though again this isn't a law that must be followed.

Just do test samples and see what you are comfortable with. Do some upper and lower quality tests. Then you can see what you are comfortable with.

Unless it is a rather large capacity player you will probably want to use a lower bitrate to fit more videos on it. Although if it has a slot for memory card expansion than that wouldn't be as vitale.

But again the best suggestion is to do trial and error and keep note of what looks best to you. Just remember on a 2 inch screen your not going to need a dvd quality file as the detail won't be as high.

[jagabo]

Forget bitrate. Use constant quality encoding. You always get exactly the right bitrate for the video you are encoding. Of course, your playback device may have restrictions on bitrates.

[cd090580]

Thanks. I will do some experiments.

Last question, the resolution is 220*176 which means 1.25 aspect ratio.

So how can I convert videos to keep the right aspect ratio of source video (4:3, 1,77:1, 1,85:1, 2,35:1,...) ?
Thanks

[guns1inger]

What sort of video does it use ? Many of these low resolution "MP4" players use AMV, which is an mjpeg variant. They usually come with their own conversion software, and this is usually the best thing to use. My daughter has one of these players, and it's conversion tool will read AVS (Avisynth) files, so I use this to resize anything it has troubles with.

[jagabo]

Last question, the resolution is 220*176 which means 1.25 aspect ratio.

So how can I convert videos to keep the right aspect ratio of source video (4:3, 1,77:1, 1,85:1, 2,35:1,...) ?

It depends on whether the display uses square pixels and how it handles different video aspect ratios.

[cd090580]

The player supports AVI in XVid or Divx format

Last question, the resolution is 220*176 which means 1.25 aspect ratio.

So how can I convert videos to keep the right aspect ratio of source video (4:3, 1,77:1, 1,85:1, 2,35:1,...) ?

It depends on whether the display uses square pixels and how it handles different video aspect ratios.

How can I test that ?

[jagabo]

All you can do is make different videos and see how they look. I would make a square in the middle of a 220x176 frame with a border as a start:



Do you see all four borders? Is the square distorted?