352x240 and 720x480 mpeg2/file same size

[taurusthebull]

i recently burned a file that i encoded with tmpgenc that was video/352x240/mpeg2. audio/128kbs/48000hz. biterate/constant br/5000bps. this went on a dvd+rw (wasn`t sure if dvd player would read it) well my dvd player (sony ns315) played it fine, infact it a damn good picture. i thought i might have been onto something; making it possible for me to have smaller file size without effecting the quality and being able to put 2 movies on a blank dvd (4.7). well when i compared file sizes between 720x480/dvd and 352x240/dvd; on a 1 minute clip, the file size was exactly the same. i can`t understand how that`s possible. anybody ideas would be greatly apprieciated!

[RoopeT]

Of course the file size is the same, if you used CBR 5000 kbps on both files. Resolution has nothing to do with file size!

[anti-alias]

Setting the bitrate is essentially setting the compression *for a given resolution* ....
higher bitrate = lower compression = higher quality.

So what you have done is create a very low compression, high quality 352x240 mpeg2. Because a 720x480 has roughly 4x the number of pixels, your encoder has to compress more to maintain the same bitrate ... thus you will lose detail/quality. However, at 5000kb I think you will find the 720x480 will look better than the 352x240 ... in fact I'm positive it will. You could try 352x480 and make a judement call as to which looks better.