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Compression Bitrates

 
 
Gary Eickmeier
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      04-30-2011, 04:47 AM
I'm not sure how to say this one without exposing my ignorance
unnecessarily, but I am sometimes without a paddle on bitrates when I am
trying to convert/compress a video into another format. I have several
programs on my computer that can convert video files, and there are so many
formats and purposes for these conversions that the program cannot always
give you a ballpark number in the presets.

For example, I have finished editing a Hi Def video, and I want to convert
it to Windows Media File, or Quicktime. I can figure out most everything
except when it asks me what bitrate I want, or it offers me a very low
bitrate in the presets, it hits me cold what a good figure would be. What I
want is a simple table for most situations with bitrates for upper and lower
quality limits of the various formats. So it might say, Windows Media Video,
Hi Def, full frame, you want 2000 to 5000 kbps.

I realize that I could make my own table after a lot of experimentation, but
why don't The Videoguys or someone already have such tables? My Premiere
textbooks aren't real helpful either. Perhaps there is a website that lays
this out for me. Anyone know?

Gary Eickmeier


 
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Smarty
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Posts: n/a

 
      04-30-2011, 04:51 AM
On 4/30/2011 12:47 AM, Gary Eickmeier wrote:
> I'm not sure how to say this one without exposing my ignorance
> unnecessarily, but I am sometimes without a paddle on bitrates when I am
> trying to convert/compress a video into another format. I have several
> programs on my computer that can convert video files, and there are so many
> formats and purposes for these conversions that the program cannot always
> give you a ballpark number in the presets.
>
> For example, I have finished editing a Hi Def video, and I want to convert
> it to Windows Media File, or Quicktime. I can figure out most everything
> except when it asks me what bitrate I want, or it offers me a very low
> bitrate in the presets, it hits me cold what a good figure would be. What I
> want is a simple table for most situations with bitrates for upper and lower
> quality limits of the various formats. So it might say, Windows Media Video,
> Hi Def, full frame, you want 2000 to 5000 kbps.
>
> I realize that I could make my own table after a lot of experimentation, but
> why don't The Videoguys or someone already have such tables? My Premiere
> textbooks aren't real helpful either. Perhaps there is a website that lays
> this out for me. Anyone know?
>
> Gary Eickmeier
>
>

Gary,
The information below is copied directly from Wikipedia/Bitrates
description of bitrates for audio and video. Other "rules of thumb" and
ball-park estimates can be found with Googling "typical video bitrates".


Video

* 16 kbit/s – videophone <http://en.wikipedia.org/wiki/Videophone>
quality (minimum necessary for a consumer-acceptable "talking
head" picture using various video compression schemes)
* 128 – 384 kbit/s – business-oriented videoconferencing
<http://en.wikipedia.org/wiki/Videoconferencing> quality using
video compression
* 1.15 Mbit/s max – VCD <http://en.wikipedia.org/wiki/VCD> quality
(using MPEG1 <http://en.wikipedia.org/wiki/MPEG-1>
compression)^[6] <http://en.wikipedia.org/wiki/Bit_rate#cite_note-5>
* 3.5 Mbit/s typ - Standard-definition television
<http://en.wikipedia.org/wiki/Standard-definition_television>
quality (with bit-rate reduction from MPEG-2 compression)
* 9.8 Mbit/s max – DVD <http://en.wikipedia.org/wiki/DVD> (using
MPEG2 <http://en.wikipedia.org/wiki/MPEG2> compression)^[7]
<http://en.wikipedia.org/wiki/Bit_rate#cite_note-6>
* 8 to 15 Mbit/s typ – HDTV
<http://en.wikipedia.org/wiki/High-definition_television> quality
(with bit-rate reduction from MPEG-4 AVC compression)
* 19 Mbit/s approximate - HDV <http://en.wikipedia.org/wiki/HDV>
720p (using MPEG2 <http://en.wikipedia.org/wiki/MPEG2>
compression)^[8]
<http://en.wikipedia.org/wiki/Bit_rate#cite_note-hdv-info.org-7>
* 24 Mbit/s max - AVCHD <http://en.wikipedia.org/wiki/AVCHD> (using
MPEG4 AVC <http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC>
compression)^[9] <http://en.wikipedia.org/wiki/Bit_rate#cite_note-8>
* 25 Mbit/s approximate - HDV <http://en.wikipedia.org/wiki/HDV>
1080i (using MPEG2 <http://en.wikipedia.org/wiki/MPEG2>
compression)^[8]
<http://en.wikipedia.org/wiki/Bit_rate#cite_note-hdv-info.org-7>
* 29.4 Mbit/s max – HD DVD <http://en.wikipedia.org/wiki/HD_DVD>
* 40 Mbit/s max – Blu-ray Disc
<http://en.wikipedia.org/wiki/Blu-ray_Disc> (using MPEG2
<http://en.wikipedia.org/wiki/MPEG2>, AVC
<http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC> or VC-1
<http://en.wikipedia.org/wiki/VC-1> compression)^[10]
<http://en.wikipedia.org/wiki/Bit_rate#cite_note-9>


 
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Gary Eickmeier
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Posts: n/a

 
      04-30-2011, 05:36 AM

"Smarty" <(E-Mail Removed)> wrote in message
news:ipg4g9$khk$(E-Mail Removed)...
> On 4/30/2011 12:47 AM, Gary Eickmeier wrote:
>> I'm not sure how to say this one without exposing my ignorance
>> unnecessarily, but I am sometimes without a paddle on bitrates when I am
>> trying to convert/compress a video into another format. I have several
>> programs on my computer that can convert video files, and there are so
>> many
>> formats and purposes for these conversions that the program cannot always
>> give you a ballpark number in the presets.
>>
>> For example, I have finished editing a Hi Def video, and I want to
>> convert
>> it to Windows Media File, or Quicktime. I can figure out most everything
>> except when it asks me what bitrate I want, or it offers me a very low
>> bitrate in the presets, it hits me cold what a good figure would be. What
>> I
>> want is a simple table for most situations with bitrates for upper and
>> lower
>> quality limits of the various formats. So it might say, Windows Media
>> Video,
>> Hi Def, full frame, you want 2000 to 5000 kbps.
>>
>> I realize that I could make my own table after a lot of experimentation,
>> but
>> why don't The Videoguys or someone already have such tables? My Premiere
>> textbooks aren't real helpful either. Perhaps there is a website that
>> lays
>> this out for me. Anyone know?
>>
>> Gary Eickmeier
>>
>>

> Gary,
> The information below is copied directly from Wikipedia/Bitrates
> description of bitrates for audio and video. Other "rules of thumb" and
> ball-park estimates can be found with Googling "typical video bitrates".
>
>
> Video
>
> * 16 kbit/s - videophone <http://en.wikipedia.org/wiki/Videophone>
> quality (minimum necessary for a consumer-acceptable "talking
> head" picture using various video compression schemes)
> * 128 - 384 kbit/s - business-oriented videoconferencing
> <http://en.wikipedia.org/wiki/Videoconferencing> quality using
> video compression
> * 1.15 Mbit/s max - VCD <http://en.wikipedia.org/wiki/VCD> quality
> (using MPEG1 <http://en.wikipedia.org/wiki/MPEG-1>
> compression)^[6] <http://en.wikipedia.org/wiki/Bit_rate#cite_note-5>
> * 3.5 Mbit/s typ - Standard-definition television
> <http://en.wikipedia.org/wiki/Standard-definition_television>
> quality (with bit-rate reduction from MPEG-2 compression)
> * 9.8 Mbit/s max - DVD <http://en.wikipedia.org/wiki/DVD> (using
> MPEG2 <http://en.wikipedia.org/wiki/MPEG2> compression)^[7]
> <http://en.wikipedia.org/wiki/Bit_rate#cite_note-6>
> * 8 to 15 Mbit/s typ - HDTV
> <http://en.wikipedia.org/wiki/High-definition_television> quality
> (with bit-rate reduction from MPEG-4 AVC compression)
> * 19 Mbit/s approximate - HDV <http://en.wikipedia.org/wiki/HDV>
> 720p (using MPEG2 <http://en.wikipedia.org/wiki/MPEG2>
> compression)^[8]
> <http://en.wikipedia.org/wiki/Bit_rate#cite_note-hdv-info.org-7>
> * 24 Mbit/s max - AVCHD <http://en.wikipedia.org/wiki/AVCHD> (using
> MPEG4 AVC <http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC>
> compression)^[9] <http://en.wikipedia.org/wiki/Bit_rate#cite_note-8>
> * 25 Mbit/s approximate - HDV <http://en.wikipedia.org/wiki/HDV>
> 1080i (using MPEG2 <http://en.wikipedia.org/wiki/MPEG2>
> compression)^[8]
> <http://en.wikipedia.org/wiki/Bit_rate#cite_note-hdv-info.org-7>
> * 29.4 Mbit/s max - HD DVD <http://en.wikipedia.org/wiki/HD_DVD>
> * 40 Mbit/s max - Blu-ray Disc
> <http://en.wikipedia.org/wiki/Blu-ray_Disc> (using MPEG2
> <http://en.wikipedia.org/wiki/MPEG2>, AVC
> <http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC> or VC-1
> <http://en.wikipedia.org/wiki/VC-1> compression)^[10]
> <http://en.wikipedia.org/wiki/Bit_rate#cite_note-9>
>


So now you see what I mean. I don't believe all of this table. DVD I know is
between 2 and 4 Mbit/s, not 9.8. And where are the compressed formats, WMV
and Quicktime? Again, my example problem was I have made a Hi Def video and
I want to convert it to WMV at full frame size, 29.97 fps, high quality. How
would you look that up on that table?

Gary Eickmeier


 
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BJ
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Posts: n/a

 
      04-30-2011, 10:56 AM
On Sat, 30 Apr 2011 01:36:57 -0400, "Gary Eickmeier"
<(E-Mail Removed)> wrote:

>So now you see what I mean. I don't believe all of this table. DVD I know is
>between 2 and 4 Mbit/s, not 9.8. And where are the compressed formats, WMV
>and Quicktime? Again, my example problem was I have made a Hi Def video and
>I want to convert it to WMV at full frame size, 29.97 fps, high quality. How
>would you look that up on that table?
>
>Gary Eickmeier
>


I believe the values Smarty posted are maximum values. The DVD's you
watch may be between 2-4 mb/s, but the maximum value for DVD (which
is mpeg2 ONLY) is 9.8 mb/s. (8 mb/s video, 1.8 mb/s audio, iirc.)

THAT'S PART OF THE DVD STANDARD. If you don't know what the
standards are for the different formats, then you're probably
going to have difficulties to start with.

Those formats which he posted are *all* standard formats. Once you
start transcoding into wmv (don't know about quicktime, but it's
probably the same), you can create any video size at any bit rate,
so there are *no* standards.

Also remember detail is what really pushes bit-rates. A video of
a stationary white wall can have a lower bit rate than a moving
crowd scene while still showing the same amount of detail. It's
how the compression formats work. So trying to get someone
to tell you what values you should use for your video is probably
useless.

I'd take a few short clips and transcode to the final format you
want using several bit rates and look at the results. You're
the final arbiter on what the final result should look like anyway.
You can make your video look anywhere from a netflix stream to
Blu-Ray. There are those who think a stream from netflix is all
the resolution they'd ever want...

BJ
--
I have nothing important to say...
 
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Mxsmanic
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Posts: n/a

 
      04-30-2011, 01:13 PM
The problem is that there's no direct correlation between image quality,
resolution, frame rates, etc., and bitrates.

Most good, modern compression algorithms produce bitstreams of variable
length, depending on the nature of the input and the degree of compression
chosen through various variables used by the algorithm.

The complexity of the original content is very important for most algorithms.
A static title on the screen compresses much more dramatically than a screen
that shows random static or snow (which typically cannot be compressed at
all). This implies that, for example, a sports video won't compress as much as
a video slideshow of landscapes. The bitrate will thus vary depending on the
type of video content being compressed.

When bitrates are given, they are usually the maximum rates the equipment can
handle or the worst-case rates for compression of any likely real-world
content.

The Wikipedia table numbers are just ballpark estimates, for the reasons
stated above.
 
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David Ruether
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      04-30-2011, 01:19 PM

"Gary Eickmeier" <(E-Mail Removed)> wrote in message
news:1bNup.33209$(E-Mail Removed) m...
> "Smarty" <(E-Mail Removed)> wrote in message
> news:ipg4g9$khk$(E-Mail Removed)...
>> On 4/30/2011 12:47 AM, Gary Eickmeier wrote:


>>> I'm not sure how to say this one without exposing my ignorance
>>> unnecessarily, but I am sometimes without a paddle on bitrates when I am
>>> trying to convert/compress a video into another format. I have several
>>> programs on my computer that can convert video files, and there are so
>>> many
>>> formats and purposes for these conversions that the program cannot
>>> always
>>> give you a ballpark number in the presets.
>>>
>>> For example, I have finished editing a Hi Def video, and I want to
>>> convert
>>> it to Windows Media File, or Quicktime. I can figure out most everything
>>> except when it asks me what bitrate I want, or it offers me a very low
>>> bitrate in the presets, it hits me cold what a good figure would be.
>>> What I
>>> want is a simple table for most situations with bitrates for upper and
>>> lower
>>> quality limits of the various formats. So it might say, Windows Media
>>> Video,
>>> Hi Def, full frame, you want 2000 to 5000 kbps.
>>>
>>> I realize that I could make my own table after a lot of experimentation,
>>> but
>>> why don't The Videoguys or someone already have such tables? My Premiere
>>> textbooks aren't real helpful either. Perhaps there is a website that
>>> lays
>>> this out for me. Anyone know?
>>>
>>> Gary Eickmeier


>> Gary,
>> The information below is copied directly from Wikipedia/Bitrates
>> description of bitrates for audio and video. Other "rules of thumb" and
>> ball-park estimates can be found with Googling "typical video bitrates".
>>
>> Video
>>
>> * 16 kbit/s - videophone <http://en.wikipedia.org/wiki/Videophone>
>> quality (minimum necessary for a consumer-acceptable "talking
>> head" picture using various video compression schemes)
>> * 128 - 384 kbit/s - business-oriented videoconferencing
>> <http://en.wikipedia.org/wiki/Videoconferencing> quality using
>> video compression
>> * 1.15 Mbit/s max - VCD <http://en.wikipedia.org/wiki/VCD> quality
>> (using MPEG1 <http://en.wikipedia.org/wiki/MPEG-1>
>> compression)^[6] <http://en.wikipedia.org/wiki/Bit_rate#cite_note-5>
>> * 3.5 Mbit/s typ - Standard-definition television
>> <http://en.wikipedia.org/wiki/Standard-definition_television>
>> quality (with bit-rate reduction from MPEG-2 compression)
>> * 9.8 Mbit/s max - DVD <http://en.wikipedia.org/wiki/DVD> (using
>> MPEG2 <http://en.wikipedia.org/wiki/MPEG2> compression)^[7]
>> <http://en.wikipedia.org/wiki/Bit_rate#cite_note-6>
>> * 8 to 15 Mbit/s typ - HDTV
>> <http://en.wikipedia.org/wiki/High-definition_television> quality
>> (with bit-rate reduction from MPEG-4 AVC compression)
>> * 19 Mbit/s approximate - HDV <http://en.wikipedia.org/wiki/HDV>
>> 720p (using MPEG2 <http://en.wikipedia.org/wiki/MPEG2>
>> compression)^[8]
>> <http://en.wikipedia.org/wiki/Bit_rate#cite_note-hdv-info.org-7>
>> * 24 Mbit/s max - AVCHD <http://en.wikipedia.org/wiki/AVCHD> (using
>> MPEG4 AVC <http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC>
>> compression)^[9] <http://en.wikipedia.org/wiki/Bit_rate#cite_note-8>
>> * 25 Mbit/s approximate - HDV <http://en.wikipedia.org/wiki/HDV>
>> 1080i (using MPEG2 <http://en.wikipedia.org/wiki/MPEG2>
>> compression)^[8]
>> <http://en.wikipedia.org/wiki/Bit_rate#cite_note-hdv-info.org-7>
>> * 29.4 Mbit/s max - HD DVD <http://en.wikipedia.org/wiki/HD_DVD>
>> * 40 Mbit/s max - Blu-ray Disc
>> <http://en.wikipedia.org/wiki/Blu-ray_Disc> (using MPEG2
>> <http://en.wikipedia.org/wiki/MPEG2>, AVC
>> <http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC> or VC-1
>> <http://en.wikipedia.org/wiki/VC-1> compression)^[10]
>> <http://en.wikipedia.org/wiki/Bit_rate#cite_note-9>


> So now you see what I mean. I don't believe all of this table. DVD I know
> is between 2 and 4 Mbit/s, not 9.8. And where are the compressed formats,
> WMV and Quicktime? Again, my example problem was I have made a Hi Def
> video and I want to convert it to WMV at full frame size, 29.97 fps, high
> quality. How would you look that up on that table?
>
> Gary Eickmeier


[BJ's response:
"I believe the values Smarty posted are maximum values. The DVD's you
watch may be between 2-4 mb/s, but the maximum value for DVD (which
is mpeg2 ONLY) is 9.8 mb/s. (8 mb/s video, 1.8 mb/s audio, iirc.)

THAT'S PART OF THE DVD STANDARD. If you don't know what the
standards are for the different formats, then you're probably
going to have difficulties to start with.

Those formats which he posted are *all* standard formats. Once you
start transcoding into wmv (don't know about quicktime, but it's
probably the same), you can create any video size at any bit rate,
so there are *no* standards.

Also remember detail is what really pushes bit-rates. A video of
a stationary white wall can have a lower bit rate than a moving
crowd scene while still showing the same amount of detail. It's
how the compression formats work. So trying to get someone
to tell you what values you should use for your video is probably
useless.

I'd take a few short clips and transcode to the final format you
want using several bit rates and look at the results. You're
the final arbiter on what the final result should look like anyway.
You can make your video look anywhere from a netflix stream to
Blu-Ray. There are those who think a stream from netflix is all
the resolution they'd ever want...

BJ"]

For Gary, I do as "BJ" suggests, and take a *short* clip of high
quality and detail (with motion in part of it), and I convert it to
whatever I want to try (within the limits of the maximum data
rate for the new format, or the lower data rate I want to try out)
and return it to the timeline in synch with the original. I may try
several different transcodes, each on a new track in synch with
the original clip. Once on the timeline, I choose a particularly
detailed frame in the original to place the cursor on, which then
(using a 1920x1080 LCD monitor for the video) permits me to
see the differences when tracks are switched on/off to compare
their contents with the original material. It can also be useful to
play the tracks (assuming that their formats play smoothly from
the timeline - or in the case of Vegas, RAM previews can be
made to guarantee smooth playback) to see what the clips
look like in motion.
--DR



 
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CLicker@invalid.org
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Posts: n/a

 
      04-30-2011, 04:03 PM
On Sat, 30 Apr 2011 00:47:15 -0400, "Gary Eickmeier"
<(E-Mail Removed)> wrote:

>I'm not sure how to say this one without exposing my ignorance
>unnecessarily, but I am sometimes without a paddle on bitrates when I am
>trying to convert/compress a video into another format. I have several
>programs on my computer that can convert video files, and there are so many
>formats and purposes for these conversions that the program cannot always
>give you a ballpark number in the presets.
>
>For example, I have finished editing a Hi Def video, and I want to convert
>it to Windows Media File, or Quicktime. I can figure out most everything
>except when it asks me what bitrate I want, or it offers me a very low
>bitrate in the presets, it hits me cold what a good figure would be. What I
>want is a simple table for most situations with bitrates for upper and lower
>quality limits of the various formats. So it might say, Windows Media Video,
>Hi Def, full frame, you want 2000 to 5000 kbps.
>
>I realize that I could make my own table after a lot of experimentation, but
>why don't The Videoguys or someone already have such tables? My Premiere
>textbooks aren't real helpful either. Perhaps there is a website that lays
>this out for me. Anyone know?
>
>Gary Eickmeier
>


I've never worked with WMV or QT video but have converted analog and
HDTV video captures using either h.263 or h.264 DivX codecs. My
intent was merely to reduce file size but with as little sacrifice in
quality as possible. At the very least this meant to me that I needed
a two pass encoder and a suggested bit range that would accommodate
what I perceived to be typical lighting and motion for the shows I was
going to convert. However, it was still necessary to tweak the
average for those videos which were obviously outside those
parameters, namely more motion and/or darker scenes; underwater and
gradient coloring, such as sky and painted walls, require another
tweak to minimize stair stepping.

One early HD effort was a PBS video of the Monterey Aquarium when they
first introduced a Great White Shark to their collection. This HDTV
show was captured by a Hauppauge analog-to-digital USB box via SVideo
from a Motorola HD-DVR and the resulting 13 mbps CBR MPEG2 file was
then compressed to 2 mbps VBR. This 50 minute video still shows very
well on a 55" HDTV.

In the long run, I settled on a typical range of 8000 (for the very
dark or fast scenes) to 1000 (for their opposites) with a target size
of about 25% of the original. Originally using Flask-MPEG and
eventually VDub-MPEG, both with DivX h.263 codecs. The container used
was .AVI. The process typically consumed 2.5x playtime on P4 type
CPUs.

Lately, I've tested DivX's h.264 converter which does superb one pass
work at about 4:1 reduction in size but, sadly, takes 5x play time on
a 2 GHz quad to produce this result. The PC used has an h.264 decoder
in its GPU but is of little use for making h.264 encodings. The
container used is .MKV.

However, with the capacity and price of HDD dramatically outstripping
optical media, I've long ago stopped converting anything from its
captured bit rate and quality. With 2 TB drives now below $80 there's
little concern should another disc or more be needed for the library.
While AVI, MPG, MKV, and TS files (among others) cannot be played
without the user needing a codec or piece of hardware to assist, its
not been a major hurdle to us. We often take along a few hard drives,
an IcyDock single bay transport, and a WD TV Live Plus player to
entertain others in their homes or a vacation spot.
 
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Smarty
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Posts: n/a

 
      04-30-2011, 05:51 PM
On 4/30/2011 12:03 PM, (E-Mail Removed) wrote:
> On Sat, 30 Apr 2011 00:47:15 -0400, "Gary Eickmeier"
> <(E-Mail Removed)> wrote:
>
>> I'm not sure how to say this one without exposing my ignorance
>> unnecessarily, but I am sometimes without a paddle on bitrates when I am
>> trying to convert/compress a video into another format. I have several
>> programs on my computer that can convert video files, and there are so many
>> formats and purposes for these conversions that the program cannot always
>> give you a ballpark number in the presets.
>>
>> For example, I have finished editing a Hi Def video, and I want to convert
>> it to Windows Media File, or Quicktime. I can figure out most everything
>> except when it asks me what bitrate I want, or it offers me a very low
>> bitrate in the presets, it hits me cold what a good figure would be. What I
>> want is a simple table for most situations with bitrates for upper and lower
>> quality limits of the various formats. So it might say, Windows Media Video,
>> Hi Def, full frame, you want 2000 to 5000 kbps.
>>
>> I realize that I could make my own table after a lot of experimentation, but
>> why don't The Videoguys or someone already have such tables? My Premiere
>> textbooks aren't real helpful either. Perhaps there is a website that lays
>> this out for me. Anyone know?
>>
>> Gary Eickmeier
>>

> I've never worked with WMV or QT video but have converted analog and
> HDTV video captures using either h.263 or h.264 DivX codecs. My
> intent was merely to reduce file size but with as little sacrifice in
> quality as possible. At the very least this meant to me that I needed
> a two pass encoder and a suggested bit range that would accommodate
> what I perceived to be typical lighting and motion for the shows I was
> going to convert. However, it was still necessary to tweak the
> average for those videos which were obviously outside those
> parameters, namely more motion and/or darker scenes; underwater and
> gradient coloring, such as sky and painted walls, require another
> tweak to minimize stair stepping.
>
> One early HD effort was a PBS video of the Monterey Aquarium when they
> first introduced a Great White Shark to their collection. This HDTV
> show was captured by a Hauppauge analog-to-digital USB box via SVideo
> from a Motorola HD-DVR and the resulting 13 mbps CBR MPEG2 file was
> then compressed to 2 mbps VBR. This 50 minute video still shows very
> well on a 55" HDTV.
>
> In the long run, I settled on a typical range of 8000 (for the very
> dark or fast scenes) to 1000 (for their opposites) with a target size
> of about 25% of the original. Originally using Flask-MPEG and
> eventually VDub-MPEG, both with DivX h.263 codecs. The container used
> was .AVI. The process typically consumed 2.5x playtime on P4 type
> CPUs.
>
> Lately, I've tested DivX's h.264 converter which does superb one pass
> work at about 4:1 reduction in size but, sadly, takes 5x play time on
> a 2 GHz quad to produce this result. The PC used has an h.264 decoder
> in its GPU but is of little use for making h.264 encodings. The
> container used is .MKV.
>
> However, with the capacity and price of HDD dramatically outstripping
> optical media, I've long ago stopped converting anything from its
> captured bit rate and quality. With 2 TB drives now below $80 there's
> little concern should another disc or more be needed for the library.
> While AVI, MPG, MKV, and TS files (among others) cannot be played
> without the user needing a codec or piece of hardware to assist, its
> not been a major hurdle to us. We often take along a few hard drives,
> an IcyDock single bay transport, and a WD TV Live Plus player to
> entertain others in their homes or a vacation spot.


Gary, et al,

Sorry if my prior reply was too pithy and overly simplistic. I entirely
concur with the advice from BJ and David to create some short samples to
see what ultimate encoding / transcoding meets your needs.

Since both Quicktime and Windows Media formats are containers for
similarly encoded h.264 video and audio codecs, you should expect the
results for a given video (and audio) bitrate to be roughly equivalent.

If your intention is to preserve the original content without further
severe degradation, you could apply a very simple 'rule of thumb' and
divide the file size by the time duration of the clip to see what the
original content bitrate is. A 10 megabyte clip which runs for 5
seconds, for example, would have a bitrate of 2 megabytes per second, or
16 megabits/sec. This rate becomes your "starting point" as a reference
to what you initially are dealing with, adding no degradation.

Depending upon many variables, most notably the distribution media
format you intend (such as Internet web serving, BluRay disk,
iPhone/iPod compatible, etc.) you can then begin to degrade the image as
required, also noting that the content you are compressing varies
tremendously with regard to how quickly it reveals compression artifacts.

As others have noted, the degree of image quality degradation can be
slight for static, slow moving, simple images using the very same
compression ratio which would utterly destroy fast moving, complex video.

Thus, a simple table of "correct" values is nearly meaningless, and only
the most simple generalizations such as the Wiki article I sent earlier
can be used in a very generic way.

Taking the actual clip, in particular the most stressing portions, and
experimenting with bitrates in the format of your intended distribution,
is the RIGHT WAY to ultimately determine what you should be using. My
apologies for not amplifying these points in my 1:00 A.M. reply early
this morning. I was not up for any more elaboration at that time of day
/ night.

Hope this helps Gary,

Smarty

 
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Gary Eickmeier
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      04-30-2011, 05:54 PM

"David Ruether" <(E-Mail Removed)> wrote in message
news:iph292$8h6$(E-Mail Removed)...

> For Gary, I do as "BJ" suggests, and take a *short* clip of high
> quality and detail (with motion in part of it), and I convert it to
> whatever I want to try (within the limits of the maximum data
> rate for the new format, or the lower data rate I want to try out)
> and return it to the timeline in synch with the original. I may try
> several different transcodes, each on a new track in synch with
> the original clip. Once on the timeline, I choose a particularly
> detailed frame in the original to place the cursor on, which then
> (using a 1920x1080 LCD monitor for the video) permits me to
> see the differences when tracks are switched on/off to compare
> their contents with the original material. It can also be useful to
> play the tracks (assuming that their formats play smoothly from
> the timeline - or in the case of Vegas, RAM previews can be
> made to guarantee smooth playback) to see what the clips
> look like in motion.
> --DR


OK, come on fellers - the reason for my question should be apparent now. I
am not going to be fooling around with all these experiments every time I
need to encode something. As I said, I suppose I will have to do the work
and make my own table, but I am very surprised that someone has not done
this already. I have been stumbling along so far by trying to trust the
preset rates, but of course that assumes that it is possible to have the
programs compute all of the possible preset bitrates that I will need at a
given moment. Doesn't seem to work out that way, and my ignorance bugs me.

So hey, let's get together and make a GOOD, USEFUL chart that we can all
use, and maybe send it to The Videoguys to publish. There are only so many
commonly encountered situations that we need to address.

OK, couple more responses below that I haven't yet read. Maybe they have
done it!

Gary


 
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Gary Eickmeier
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      04-30-2011, 06:02 PM

<CLicker> wrote in message
news:(E-Mail Removed)...
> On Sat, 30 Apr 2011 00:47:15 -0400, "Gary Eickmeier"
> <(E-Mail Removed)> wrote:
>
>>I'm not sure how to say this one without exposing my ignorance
>>unnecessarily, but I am sometimes without a paddle on bitrates when I am
>>trying to convert/compress a video into another format. I have several
>>programs on my computer that can convert video files, and there are so
>>many
>>formats and purposes for these conversions that the program cannot always
>>give you a ballpark number in the presets.
>>
>>For example, I have finished editing a Hi Def video, and I want to convert
>>it to Windows Media File, or Quicktime. I can figure out most everything
>>except when it asks me what bitrate I want, or it offers me a very low
>>bitrate in the presets, it hits me cold what a good figure would be. What
>>I
>>want is a simple table for most situations with bitrates for upper and
>>lower
>>quality limits of the various formats. So it might say, Windows Media
>>Video,
>>Hi Def, full frame, you want 2000 to 5000 kbps.
>>
>>I realize that I could make my own table after a lot of experimentation,
>>but
>>why don't The Videoguys or someone already have such tables? My Premiere
>>textbooks aren't real helpful either. Perhaps there is a website that lays
>>this out for me. Anyone know?
>>
>>Gary Eickmeier
>>

>
> I've never worked with WMV or QT video but have converted analog and
> HDTV video captures using either h.263 or h.264 DivX codecs. My
> intent was merely to reduce file size but with as little sacrifice in
> quality as possible. At the very least this meant to me that I needed
> a two pass encoder and a suggested bit range that would accommodate
> what I perceived to be typical lighting and motion for the shows I was
> going to convert. However, it was still necessary to tweak the
> average for those videos which were obviously outside those
> parameters, namely more motion and/or darker scenes; underwater and
> gradient coloring, such as sky and painted walls, require another
> tweak to minimize stair stepping.
>
> One early HD effort was a PBS video of the Monterey Aquarium when they
> first introduced a Great White Shark to their collection. This HDTV
> show was captured by a Hauppauge analog-to-digital USB box via SVideo
> from a Motorola HD-DVR and the resulting 13 mbps CBR MPEG2 file was
> then compressed to 2 mbps VBR. This 50 minute video still shows very
> well on a 55" HDTV.
>
> In the long run, I settled on a typical range of 8000 (for the very
> dark or fast scenes) to 1000 (for their opposites) with a target size
> of about 25% of the original. Originally using Flask-MPEG and
> eventually VDub-MPEG, both with DivX h.263 codecs. The container used
> was .AVI. The process typically consumed 2.5x playtime on P4 type
> CPUs.
>
> Lately, I've tested DivX's h.264 converter which does superb one pass
> work at about 4:1 reduction in size but, sadly, takes 5x play time on
> a 2 GHz quad to produce this result. The PC used has an h.264 decoder
> in its GPU but is of little use for making h.264 encodings. The
> container used is .MKV.
>
> However, with the capacity and price of HDD dramatically outstripping
> optical media, I've long ago stopped converting anything from its
> captured bit rate and quality. With 2 TB drives now below $80 there's
> little concern should another disc or more be needed for the library.
> While AVI, MPG, MKV, and TS files (among others) cannot be played
> without the user needing a codec or piece of hardware to assist, its
> not been a major hurdle to us. We often take along a few hard drives,
> an IcyDock single bay transport, and a WD TV Live Plus player to
> entertain others in their homes or a vacation spot.


To all - there is a feature on my Premiere encoder that has a window that is
supposed to show you the material that is input vs. the resulting output
video. I haven't experimented with that enough to know how accurate it is in
predicting what the compressed stuff will look like, but if it works it
would be a godsend to tell me both aspect ratio and video quality of the
resulting encode. I will make a point of it to try this with various
settings and see if this is one answer to my question.

Gary Eickmeier


 
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