POV-Ray : Newsgroups : povray.off-topic : Bitrate and other settings for H.264? Server Time
4 Nov 2024 19:16:13 EST (-0500)
  Bitrate and other settings for H.264? (Message 1 to 7 of 7)  
From: Chambers
Subject: Bitrate and other settings for H.264?
Date: 3 Feb 2008 21:44:32
Message: <47a67c10$1@news.povray.org>
So I finally have the hard drive space to start ripping my DVDs to my PC 
(in a few months, I'll buy 3 1TB disks for a raid 5 array, to store all 
my media on - but for now, I'll just rip part of my collection).  I'm 
using TMPGEnc to encode them as .mp4 files for iTunes, and I'm trying to 
figure out good settings for them.

Unfortunately, creating various setups, testing them, and comparing them 
is rather time consuming.

Does anyone have some suggestions for what I should use?

I tried 800kb average, 1500 max for full resolution rips, but on scenes 
with a lot of movement this ends up with quite blocky results.  I'm 
thinking of upping this to 1500 average, 2500max.

Also, some of my stuff doesn't need full resolution, so I drop the frame 
size down to 480x320 (from 720x480).  For this, so far it seems that 350 
average is good enough, but again I'd like to hear from others who have 
been through this.

Any advice?

And does it really help that much using 2 pass VBR, instead of 1 pass? 
(I'm willing to live with the additional encoding time if it makes a 
difference, but I haven't tried two side by side encodes to see the 
quality difference).

-- 
...Ben Chambers
ben at pacific web guy dot com (no spaces)
www.pacificwebguy.com


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From: Invisible
Subject: Re: Bitrate and other settings for H.264?
Date: 4 Feb 2008 04:38:41
Message: <47a6dd21$1@news.povray.org>
By an ironic twist of fate, last night I was staring at my PC trying to 
figure out how to convince ArcSoft DVD Creator to create DVDs that 
aren't horribly blocky. It's currently using "ArcSoft SmartRender(tm) 
automatic bitrate selection", but there is a manual option. Hmm, I 
wonder what the maximum bitrate for a DVD is?

...according to Wikipedia, 9.8 Mbit/sec. I have a feeling it won't be 
possible to get a crisp, sharp picture at that bitrate. :-(

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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From: Tor Olav Kristensen
Subject: Re: Bitrate and other settings for H.264?
Date: 4 Feb 2008 16:04:54
Message: <47a77df6$1@news.povray.org>
Invisible wrote:
> By an ironic twist of fate, last night I was staring at my PC trying to
> figure out how to convince ArcSoft DVD Creator to create DVDs that
> aren't horribly blocky. It's currently using "ArcSoft SmartRender(tm)
> automatic bitrate selection", but there is a manual option. Hmm, I
> wonder what the maximum bitrate for a DVD is?
> 
> ...according to Wikipedia, 9.8 Mbit/sec. I have a feeling it won't be
> possible to get a crisp, sharp picture at that bitrate. :-(

These might be useful:

http://dvd-hq.info/Calculator.html
http://www.videohelp.com/calc.htm

-- 
Tor Olav
http://subcube.com


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From: Chambers
Subject: Re: Bitrate and other settings for H.264?
Date: 4 Feb 2008 19:35:01
Message: <web.47a7ae3fe6e72575261d9700@news.povray.org>
Well, I ended up doing some test encodes and comparing a 1 1/2 minute sequence
from Transformers.  I uncovered a few things:

1) 2-pass VBR makes a HUGE difference over 1-pass VBR at low bitrates (I didn't
compare high bitrates).

2) Using a bitrate of >3000 yields no distinguishable improvements for visually
intensive movies (Transformers, Crouching Tiger Hidden Dragon, etc)

3) A bitrate of 1500 seems enough for other movies (Love Actually, When Harry
Met Sally, etc)

4) A lower resolution (480x320) and lower bitrate (750) is sufficient for things
such as episodes of Friends, and cartoons like The Hobbit or Winnie the Pooh.

I left it encoding some movies overnight, and I'll verify them this week to make
sure that the settings are adequate.

And Tor, thanks for the links, but I'm not concerned about the final image
size so much as the minimum quality settings needed to avoid encoding
artifacts.

.....Chambers
www.pacificwebguy.com


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From: Nicolas Alvarez
Subject: Re: Bitrate and other settings for H.264?
Date: 4 Feb 2008 20:13:01
Message: <47a7b81d$1@news.povray.org>

> And Tor, thanks for the links, but I'm not concerned about the final image
> size so much as the minimum quality settings needed to avoid encoding
> artifacts.

If you don't care about the file size, why are you setting the bitrate? 
Set the quality or the quantizer instead. The bitrate is about how much 
video data it needs per second, and it's used for example to make sure a 
movie fits a CD.


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From: Chambers
Subject: Re: Bitrate and other settings for H.264?
Date: 4 Feb 2008 21:26:46
Message: <47a7c966@news.povray.org>
Nicolas Alvarez wrote:

>> And Tor, thanks for the links, but I'm not concerned about the final 
>> image
>> size so much as the minimum quality settings needed to avoid encoding
>> artifacts.
> 
> If you don't care about the file size, why are you setting the bitrate? 
> Set the quality or the quantizer instead. The bitrate is about how much 
> video data it needs per second, and it's used for example to make sure a 
> movie fits a CD.

Because a) the version of TMPGEnc I'm using doesn't have a "Constant 
Quality" setting for h.264 files, and b) using a "constant quantization" 
method causes the resulting video to not play on my machine.

Although, I just saw that outputting a quicktime .mov file (instead of 
.mp4) allows me to use h.264, and use a quality setting there.  I think 
I'll try that next...

-- 
...Ben Chambers
ben at pacific web guy dot com (no spaces)
www.pacificwebguy.com


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From: Chambers
Subject: Re: Bitrate and other settings for H.264?
Date: 5 Feb 2008 01:21:34
Message: <47a8006e$1@news.povray.org>
Chambers wrote:
> Although, I just saw that outputting a quicktime .mov file (instead of 
> .mp4) allows me to use h.264, and use a quality setting there.  I think 
> I'll try that next...

Bah, Quicktime files take about twice as long to encode, and end up 
about twice the size of a 5000 kbit video stream in .mp4 format, without 
looking any better (and I'm scaling the final version up to fit my 
screen, so any errors should be painfully obvious).

-- 
...Ben Chambers
ben at pacific web guy dot com (no spaces)
www.pacificwebguy.com


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