--dm-preset standard and low average bitrate..

2001-10-30 17:11:16

Hi Dibrom, Sometime before there was a discussion about how to encode 1CD Divx Rips.


Well you and other recommended abr over vbr because at lower V values lame could introduce artifacts.

I have encoded Family Man for 2 CD Divx Rips with dm standard and the result is a file with an average about 130kbps.

With this low average bitrate, could dm-standard introduce artifacts? may I have to go with extreme or insane searching higher average (like 160 for example)?

I suppose, using dm-standard doesn't matter the average because there isn't more probability of introduce artifacts with lower averages....but who knows?

Thanks.

--dm-preset standard and low average bitrate..

Reply #1 – 2001-10-31 00:43:38

If --dm-preset standard actually produces a bitrate that low, chances are it will sound ok.  --dm-preset standard uses more powerful noise measuring than many other settings such as --r3mix, so it should only dip that low if it can do so with really not much distortion at all.  If you want to be safe though, I'd use --dm-preset standard -X3.  This would be overkill for most divx soundtracks by quite a bit, but in this case if you'd like that little extra assurance, it should work great.

--dm-preset standard and low average bitrate..

Reply #2 – 2001-10-31 17:44:57

Thanks very much

--dm-preset standard and low average bitrate..

Reply #3 – 2001-11-01 16:03:55

I would not be sure.

The bitrate is depending on level of sound, gain. (of course not only).

It is the question what waves you have used as input for lame !

Movies usual are very silent, only a few loud peaks because of dynamics.

ac3 to wav to mp3

in step  ac3 to wav you have to compress or normalize a little bit.
So that wavs sound loud enough. Try them.

If wavs are loud enough then converting to mp3 is no problem.

But if wavs sound all over too silent then VBR produces low bitrate mp3's.
And that could introduce artifacts.

Something else:

If ac3 is your source then 200 kbit/s average for stereo mp3  would be overkill sometimes.

Look at size of ac3 files. They have for eg. 5 channels only 384 kbit/s. So for 2 channels 128 to 160 kbit/s mp3 would be well
enough.

Should you convert ac3 to mp2 then there is a reason for using mp2 bitrate 160 to 224 kbit/s because to keep Dolby surround information you must take stereo mode, not joint stereo. So you would need a little bit more bitrate with mp2.