Does size matter?

[JamieWWE]

I have a MPG1 file 352 x 288, it is 8.21 mb in size. I converted it using TMPGENC to 640 x 480 and it is still 8.21, i have ticked non standard and using Twins Video Player, it is 640 x 480. Does this mean that in 352 x 288 files, it is really a bigger res? I mean shouldnt the file size get bigger, try it u guys and send me your thoughts

[adam]

Resolution is completely independant from filesize.

Filesize is determined by the number of bits per seconds x the total number of seconds. The only thing that affects your filesize is your bitrate.

[holistic]

FYI :

a video (frame) @ 720*480 with the same bitrate as a video @ 320*240 will have about one quarter ( 1/4 ) the amount of bits to allocate to the picture

RESULT : $hitter picture - period

BITRATE BITRATE BITRATE = 'visual' QUALITY

[AceYu]

Resolution is completely independant from filesize.

Filesize is determined by the number of bits per seconds x the total number of seconds. The only thing that affects your filesize is your bitrate

This is not strictly true, for a constant bit rate the larger the resolution, the crapper the picture. For example a full frame uncompressed at a resolution of 10x10 @10fps and a 10bit colour depth (keeping the maths simple with a whimsical example) will render a bit rate of approx 10kbit to double the resolution to 20x20 pixles renders an uncompressed bit rate of 40 kbit, to keep it to the same bit rate as the origional 3/4 the data must be gotten rid of through compression and therefore lost. This renders a lower quality picture overall. Some advanced graphic processing techiniques can be used to minimise the loss of quality which is why things like DivX and MPG1/2 work so well, but the amount of data increases exponentially as frame size increases.

A less concise explaination but amounts to the same thing as holistics'

Later BRETT

[adam]

"Resolution is completely independant from filesize.

Filesize is determined by the number of bits per seconds x the total number of seconds. The only thing that affects your filesize is your bitrate"

[This is not strictly true, for a constant bit rate the larger the resolution, the crapper the picture.

Huh? Please read my post again. You are talking about bits per pixel NOT bits per second which is what bitrate is. This discussion is about the relationship between resolution and filesize, it has absolutely nothing to do with quality.

Yes if your bitrate remains the same than as resolution increases you get less bits per pixel which translates to less quality but the filesize is the same regardless. Again, filesize is determined solely by your bitrate.