mpeg2 or mpeg4 ?

[andru123]

Hi, I have a lot of small (1mb - 200mb) movies (my own) which I encoded with different codecs/bitrates. Also resolution is different.
There are avi, mpg, wma.

I would like to archive all these movies, but:
- can I recompress some of the movies to some (better?) format, to conserve space? In any case I DO NOT WANT TO LOOSE QUALITY.
- I was under impression that mpeg2 was the best in terms of quality/compression rate. I used tmpgenc. But now I see there is MPEG4? Is it better?
- Is the a way, when convertin/recompressing movie, keep the size, framerate and bitrate the same as in the original? tmpgenc always asks you to choose these options (it does not take them from the source file being converted :( )
- are there tools to view the file's properties? (Such as: codec, its settings, bitrate, framerate, compression whtever else?) I used gspot, but it does not work for many file formats.

[jggimi]

...In any case I DO NOT WANT TO LOOSE QUALITY.... Then you do not want to reencode these videos. Copy them to data discs, either CD or DVD, as they are now.

[andru123]

Ok. I understand.

Still, is mpeg4 better then mpeg2?

[Tommy B.]

Yes, in some way.

It depends on the bitrate, whether MPEG2 or MPEG4 is better.
Generally spoken:

low bitrate = MPEG4
high bitrate = MPEG2 or MPEG4

As long as the bitrate is high enough, MPEG2 gives very good quality
which MPEG4 can not completely reach if the h263 quantinization is
used (I refer to DivX and XviD). The picture stays crisp and clear.
If you use XviD to encode your MPEG4 videos, you can choose between
different quantizer matrices like h263, MPEG and several custom ones.
So in case you want to have quality which is equal to MPEG2, you have
to use XviD with MPEG quantizer, h263 like used in DivX smoothes the
image.

But... it all depends on the resolution of the video, the complexity
etc. I think that MPEG2 is at it's best when the bitrate is not below
4000kbps (4Mbit), which actually gives a pretty large file.

In comparison, you can compress the same data with the same
resolution and quality if you use MPEG4 and aprox 2000kbps. This
should give a good result and it shows that MPEG4 behaves better
when it comes to compressing with a low bitrate, e.g. lower than
1000kbps. For comparison: SVCD has a minimum bitrate of 1600kbps,
but also a limited picture size (480x480 for NTSC, 480x576 for PAL).
If you use 1600kbps with MPEG4, the picture can stay at full´
resolution.

Hmmm... well, so much about that. MPEG4 is better than MPEG2, but
only when it is used properly (XviD + MPEG quantizer). Everything
else "might" give a bad, smoothed out result. MPEG4 is also best at
low bitrate and high bitrate, where MPEG2 can only triumph when
compressing with high bitrate.