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Is there a more detailed manual?
https://www.splasmstrands.com.splasm.com/viewtopic.php?f=11&t=122		 Page 1 of 1
Author:  viv [ Fri Dec 23, 2005 4:02 pm ]
Post subject:  Is there a more detailed manual?
1) I am confused about the encoding. Does h264 multi pass ("good" on the slider) equal h264 ("better" on the slider), or for that matter, mpeg4 ("best" on the slider). Does "Original" encoding mean better quality than both h264 and mpeg4? ? I guess what I am really saying is that I need a more detailed explanation than the "help" screen offers.

2) Thanks to Podner, I can see video Podcasts downloaded to my iPod, but only after downloading them from iTunes and then re-encoding them with Podner. This is a hassle, but Podner comes to the rescue. Why do video PodCasts not show video (only sound) when I intially download them to my iPod?

3) Will Podner provide a tool to encode part of a movie?
(thanks in advance for you answers).
Author:  keithg [ Fri Dec 23, 2005 8:20 pm ]
Post subject: 
1. Here's a brief bit to help conceptualize each Encoding setting and the Quality settings.

First, think of the Encoding as a "class" of performance characteristics, like the following:

MPEG-4: Good picture quality, fast encoding times, large file sizes
H.264: Better picture quality, slower encoding times, smaller file sizes
H.264 MultiPass: Excellent picture quality, very slow encoding times, smaller file sizes

Each Encoding can be customized by setting the Quality slider. This affects picture quality and file size, and encoding time to a far lesser degree.

In a very general sense, you might think of the apparent quality from each Encoding's Quality settings (Good, Better, Best) as leading up to the next Encoding, with its set of Quality settings. So the following list would indicate least to most apparent quality, from top to bottom:

MPEG-4, Good
MPEG-4, Better
MPEG-4, Best
H.264, Good
H.264, Better
H.264, Best
H.264 MultiPass, Good
H.264 MultiPass, Better
H.264 MultiPass, Best

But sometimes it's not quite that simple. There can be overlap between the apparent quality of some content types when encoded in both MPEG-4 and H.264 MultiPass. For instance, MPEG-4, Best can sometimes meet or even exceed the apparent quality of H.264 MultiPass, Best. That's where the other two performance characteristics come in: encoding time and file size.

To illustrate the difference in encoding time consider this example: Let's say MPEG-4 can be considered to have an encoding time of 1:1, that is, it normally takes 1 minute of processing time to encode 1 minute of video. With that as a performance baseline, here's a list of the three encodings and how they compare in encoding time:

MPEG-4: 1:1 (1 minute to encode 1 minute of source material)
H.264: 2:1 (2 minutes to encode 1 minute of source material)
H.264 MultiPass: 5:1 (5 minutes to encode 1 minute of source material)

These numbers are very general and are not necessarily the performance you will see on your Mac, and may not accurately reflect the relative encoding time for all types of material, but the point is MPEG-4 is incredibly fast compared to H.264, and H.264 is quite a bit faster than H.264 MultiPass.

Now, the only other major consideration is the amount of space each processed file will take up on your iPod. The Quality slider will increase the file size noticeably as you proceed from Good to Better and from Better to Best. Each Encoding uses the following data rates when Good, Better or Best is selected.

MPEG-4 (320x240): 512Kbps, 768Kbps, 1Mbps
MPEG-4 (480x480): 1Mbps, 1.5Mbps, 2Mbps
H.264: 320Kbps, 480Kbps, 600Kbps
H.264 MultiPass: 320Kbps, 480Kbps, 600Kbps

So, relatively speaking, each Good setting should be a little over half the size of the Best setting for any given Encoding. The Quality setting does not affect the audio data rate, sample frequency or sample size.

Our recommendation? For typical use, MPEG-4, Better or Best is fine. If you have a faster Mac, move up to H.264, Better or Best. And if you have the time and a G4 or faster Mac (do not attempt this with a G3), H.264 MultiPass, Best will generally get you the best picture quality.


2. Not sure about the issue with video podcasts. Can you point us to a specific podcast to test?


3. We are considering a feature to crop the video stream, enabling an easy 16:9 to 4:3 conversion, and the ability to trim some unwanted length off videos before processing. Thanks for asking!
Author:  viv [ Mon Dec 26, 2005 2:42 pm ]
Post subject: 
Thanks, so mpg-4 best is better quality than H.264 MultiPass. I happened to confirm this by visiting this site with examples: http://www.ilounge.com/index.php/articl ... ents/5929/
-looking forward to your updated software allowing selective clip length triming.
Author:  GrBear [ Mon Dec 26, 2005 6:37 pm ]
Post subject: 
viv wrote:
Thanks, so mpg-4 best is better quality than H.264 MultiPass.


Quality-wise they can generate very similar perceived visuals (ie: impossible to tell apart). The advantage of H.264 is a much smaller filesize, but at the cost of longer encoding time.

In other words, both encoding formats can look just as good as each other, but you have to weigh which you value more, smaller file size (H.264) or shorter compression time (MPEG-4).

Saying one is 'better quality' than the other is taking a rather simple approach and can be better clarified as 'MPG-4 meets my needs better because I'm willing to sacrifice the additional gain in filesize but save on encoding time'.

Even the article you provided the link for says the same thing:
Quote:
For iPod viewing only, H.264 is the wiser choice, so long as you’re willing to spend some extra time to initially process your video files.

That being said, if your going to be using the encoded video for any other purposes where you need a larger resolution, you have no choice but to go with MPEG-4.
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