A few questions regarding encoding

[CuriousG]

First off...time is crucial due to the amount of DVD's I have to do in short time but all the while saving as much quality as possible.

Right now I am converting DVD to MP4 format using bitrates around 1100-1300 and the file size is set to 1200mb. Using single pass rather than 2 pass just cause of the time frame. Now one question I have is what exactly does increasing the bitrate do for me and is it best to increase the file size/bitrate rather than doing a 2 pass encode? 2 pass takes far too long for me so that isnt really an option i just want to know if increasing the bitrate/file size is doing anything for me rather than doing 2 pass?
The encoder is ffmpeg and framerate is set as "same as source".

[Teegedeck]

Generally it's been the same thing since the days of MPEG-1: Higher bitrate, more details. It is not wise to do one-pass encoding based on bitrate; in scenes with lots of action for example the encoder will quickly hit the maximum bitrate and quality goes down rapidly. That is because in one-pass the bitrate is meant as 'bitrate across a short timespan' while in two-pass it is meant as 'bitrate across the whole length of the movie'. Logically in the second case the bitrate can be distributed in a smarter way.

Rather encode quality-based if encoding-time is an issue: Choose a a constant quantizer - it will give you a low bitrate in simple scenes and an appropriately high bitrate in complex scenes. If you need control over the resulting filesize, nothing can substitute two-pass, where the first pass is effectively there to make for a good guess at what (more or less) constant quantizer will be used in the second pass in order to reach the desired filesize.

[CuriousG]

Very informative indeed thank you. I am not using a PC based solution but rather a Mac version called Handbrake so I am not sure about the quantizer. I do however have a "constant bitrate" option that gives me a scale in % from 1-100 which is usually set at 50% but now I have tried to increase to 70%. Would that be a similar option to your quantizer solution?

After converting Ghost and the Darkness the action scenes seem fine without pixels but who knows on some of the others I have already done. I typically try to convert the comedies using single pass and the high action ones are 2 pass or left VOB if good enough.

I have 500gb Hitachi to put all my movies on to so space and time is crucial so this is why I seek a best solution for compressing the VOB rips to something watchable-good quality. Dont have to be the best however but would like your opinions on the situation.

For example say I am converting Matrix which we all know.

Even though it is already done 2 pass lets just say i didnt and this is what I would do for a watchable-good conversion.

Filesize=1200mb
Bitrate=1200(roughly)(it auto calculates)
FPS= same as source
Convert to: MPEG-4 with AAC Audio
Single Pass instead of 2 Pass

Using those settings do you think it would fine?

[unskinnyboy]

FPS= same as source
Quick note on this (maybe you already know) - If your source is telecined material (23.976 Film telecined to 29.971), you would need to IVTC it or you will be encoding 20% more frames than is needed. By IVTCing, you will get better quality for the same filesize as opposed to the telecined source.

[CuriousG]

Sorry that went over my head. :confused:

[unskinnyboy]

OK, I probably am taking you away from the main purpose of your thread..:/

However..

If you are dealing with PAL DVDs --> Nothing to worry. This is not applicable for you.
If you are dealing with NTSC DVDs --> Read this (http://doom9.net/ivtc-tut.htm). It will come useful.

[CuriousG]

Oh I hope I dont have to learn all that now? Time is crucial and hopefully my rips are not ruined because of this? What % of movies do you have to worry about this with do you think?

[unskinnyboy]

Rips are not ruined. You will just end up encoding unwanted frames if you don't IVTC telecined material (..and sometimes you get annoying "lines" in the picture). But maybe your encoding method already takes care of it..?

What %? I don't know..depends on what you have. As I said, if it's PAL, don't worry..If it's NTSC..read the tutorial etc.

[CuriousG]

Wow I am impressed with how helpful you have been thank you so much.
The % thing is in the program I use called Handbrake and it has a % slider for "constant quality" and just wondered if that were the same as quantizer? I am unfamiliar with quantizer cause I am trying this using another program on my Mac.

[CuriousG]

Anyone else have any input?

[jggimi]

constant quality = constant quantizer. You will not be able to predict the output file size, but you will get constant quality throughout in a single pass.

[CuriousG]

Why thanks Boss! Appreciate the clarification.
So does that increase your encoding time?