Bitrate ratios

[martinlong1978]

Hi

I've been making up a lot of DVDs with DivX avis that I've downloaded from various sources. The first stage is obviously to transcode these to MPEG 2 streams.

I actually stopped downloading MPG files completely, because, bit for bit, the quality is terrible compared to the DivX stuff - expected as it's comparing MPEG 4 with MPEG 2.

So... here's my question. What bitrate should I used to transcode a DivX file with bitrate X into an MPEG 2 file?

I've typically been using 3x the source bitrate (yeah yeah... I know about CBR and VBR), I based this on the total file size / track length.

So typically a 45minute AVI of 450Mb i would transcode (using about 4000Bps) into an mpg of about 1,400Mb. This tended to give me comparible results, with no loss of quality, to the original.

Is this overkill... would 3000bps surfice? Remember - I'm using DVDs here, so I don't have restrictions of trying to get an episode on a single CD-R, but I would still like to get more episodes per DVD if possible.

[martinlong1978]

Before you call be a fool... I did mean 3000Kbps not bps... d'oh

[setarip]

Just as a point of information, I believe the TMPGEnc DVD "wizard"/template is set to 7000kbps...

[martinlong1978]

Yes, it is, and isn't. The wizzard based this on the space available on the selected disk... as DVD-R is selected by default, and you're often only encoding 30mins to 1 hour, then it normally shows the maximum here, because it can do that, and still fit it all on the dvd. I think it may be the default anyway in TMPGEnc.

Well... 7000Kbps is exceptional quality encoding.. no artifacts, near perfect colour, pretty damn good. At 4000Kbps it is still very good... beats SVHS by a long shot. I want to use the minimum bitrate that will not degrade the quality of the original Divx AVIs.

[Soulhunter]

Re: Bitrate ratios

Originally posted by martinlong1978
I've been making up a lot of DVDs with DivX avis that I've downloaded from various sources.

Comment...

[setarip]

To Soulhunter

If you're implying that the posting is a violation of the forum's rules, it's not - as it's sufficiently vague (no movie titles, no specific source mentioned).

If you're referring to something else, please specify...

[martinlong1978]

Thanks setarip.

I don't know weather it was a derogotory comment, or what?

Because I said I had "downloaded from various sources" doesn't mean that I was doing anything illegal. It actual fact, the genre I'm interested in is quite speciallised. The work is from unsigned animators trying to put their work before a larger arena and gain exposure.

All of the material I have downloaded for this project has been in the public domain, or permission is currently being sought for it's use.

If you are going to post, please keep to topic instead of making assumptions about the nature of my activities. That only causes us to lose the benefits of great tools for legitimate purposes.

[setarip]

"Thanks setarip."

My pleasure ;>}

[Soulhunter]

Ok then, sorry...

Just asked because it was so sufficiently vague !!!

Smelled somehow like a illegal act...


Bye