What chokes H.264 footage: data rate or video dimensions?

I apologize for posting in here but this board is SO much better than the Quicktime or Compressor boards, and it's all the same workflow anyhow!
What I'm wondering is what chokes H.264 videos. Is it low bit rates? High bit rates? Big dimensions? I have an 854x480 video at 500kbps and it looks great, but even on my PowerMac there is slight stuttering, and some alpha tester feedback I've gotten tells me that a lot of slower computers are choking on the video badly.
The file size is ridiculously small, so if increasing the data rate makes it easier to decode, that would be nice.

It's neither - or either, if you will. H.264 achieves unprecedented levels of compression, which means that it's a lot more CPU-intensive to play back in real time. It simply doesn't play well on older hardware. Even slower G5s for example have problems playing back full HD H.264, particularly if it's progressive. It also depends on your GPU - certain GPUs support H.264 decoding, thus significantly offloading the CPU.
One general rule, though: the higher your data rate at any given frame size and frame rate, the less work the decoder needs to do. I'd try to go for approx. 800 kbps at your chosen frame size and see if that helps.
HTH,
Ron

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Export data rates

Hi folks,
What is the purpose of automatic data rates as opposed to specified data rates when exporting H.264 etc in FCP?
Are there ideal data rates for different dimension/levels of compression?
If so what are they and where can I find more info on them?
All a little confusing!

No one responded.

I have a question about Data Rates.

Hello All.
This is a bit of a noob question I'm sure. I don't think I really understand Data Rates and how it applies to Motion... therefore I'm not even sure what kind of questions to ask. I've been reading up online and thought I would ask some questions here. Thanks to all in advance.
I've never really worried about Data Rates until now. I am creating an Apple Motion piece with about 15 different video clips in it. And 1/2 of them have alpha channels.
What exactly is Data Rate? Is it the rate in which video clip data is read (in bits/second) from the Disc and placed into my screen? In Motion- is the Data Rate for video only? What if the clip has audio? If a HDD is simply a plastic disc with a dye read by "1" laser... how come my computer can pull "2" files off the disc at the same time? Is that what data transfer is all about? Is that were RAM comes into play?
I have crunched my clips as much as I can. They are short clips (10-15seconds each). I've compressed them with the Animation codec to preserve the Alpha channel and sized them proportionally smaller (320x240). This dropped their data rate significantly. I've also taken out any audio that was associated with them.
Is data rate what is slowing my system down?
The data rates are all under 2MBs. Some are as low as 230Kbs. They were MUCH higher. However, my animation still plays VERY slowly.
I'm running a 3GigRam Powerbook Pro 2.33GHz.
I store all my media on a 1TB GRaid Firewire 800 drive. However for portability I'm using a USB 2 smartdisk external drive. I think the speed is 5200rpm.
I'm guessing this all plays into the speed at which motion can function.
If I total my data rate transfer I get somewhere in the vicinity of 11MBs/second. Is that what motion needs for it to play smoothly a 11MBs/second data connection? USB 2.0 is like what 480Mbs/second. So there is no way it's going to play quickly. What if I played it from my hard drive? What is the data rate of my internal HDD?
I guess my overall question is.
#1. Is my thinking correct on all of these topics? Do my bits, bytes and megs make sense. Is my thought process correct?
#2. Barring getting a new machine or buying new hardware. What can I do to speed up this workflow? Working with 15 different video clips is bogging Motion down and becoming frustrating to work with. Even if only 3-4 of the clips are up at a time it bogs things down. Especially if I throw on a glow effect or something.
Any help is greatly appreciated.
-Fraky

Data rate DOES make a difference, but I'd say your real problem has more to do with the fact that you're working on a Powerbook. Motion's real time capabilities derive from the capability of the video card. Not the processor. Some cards do better than others, but laptops are not even recommended for running Motion.
To improve your workflow on a laptop will be limited, but there are a few things that you can try.
Make sure that thumbnails and previews are turned off.
Make sure that you are operating in Draft Mode.
Lower the display resolution to half, or quarter.
Don't expect to be getting real time playback. Treat it more like After Effects.
Compressing your clips into smaller Animations does help because it lowers the data rate, but you're still dealing with the animation codec which is a high data rate codec. Unfortunately, it sounds necessary in your case because you're dealing with alpha channels.
The data rate comes into play with your setup trying to play through your USB drive. USB drives are never recommended for editing or Motion work. Their throughput is not consistent enough for video work. a small FW drive would be better, though your real problem as I said is the Powerbook.
If you must work on the powerbook, then don't expect real-time playback. Instead, build your animation, step through it, and do RAM previews to view sections in real time.
I hope this helps.
Andy

Bridge 1300 building to building link for VOIP Data Rates settings and QoS

Hi,
What are the recomendations for data rates settings of wlan fo using voip in a link building to building.
Default is
speed basic-1.0 basic-2.0 basic-5.5 6.0 9.0 basic-11.0 12.0 18.0 24.0 36.0 48.0
54.0
Should i maintain or change to what?
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Thks
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OFDM is a physical layer encoding technology for transmitting signals through the RF. This method breaks one high-speed data carrier into several lower-speed carriers that transmit in parallel across the particular RF spectrum. OFDM, when used with various modulation types such as 802.11g and 802.11a, is capable of supporting data rates as high as 54 Mbps.
http://www.cisco.com/en/US/docs/voice_ip_comm/cuipph/7921g/5_0_1/english/administration/guide/7921wrnt.html#wp1085347

Encoded video does not have expected data rate

Hi
I've been encoding with Flash Media Encoder (CS3) recently
and come across a contradiction which I can't seem to make sense
of. Can it be possible that the longer the video, the harder it is
for the encoder to maintain data rate?
This was revealed when I started using FMS2 (space on a
shared server as opposed to my own server). I encoded a video at
what I thought was a data rate which was within my data rate limit
for my stream and it stuttered on playback over the stream. The FMS
supplier informed me that the FLV I thought I'd encoded at 400kbps
video 96 kbps audio actually had a data rate of around 700kbps in
total. But if I open the video in a FLV player, and look at info,
it still shows the setting I originally intended. However, my
supplier suggested checking data rate using this equation:
(filesize in MB x 8)/videoduration in seconds = video
datarate in kbits/sec
If you apply this calculation to my video it does indeed show
what they said:
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Encoded at 400kbps video - 96 kbps audio
Compressed filesize = 26,517 kbytes
Duration = 240 seconds
CALCULATION GIVES DATE RATE OF 880k/b a second
(note file contains an alpha channel)
Furthermore, applied to a shorter video, we get the following
more logical results:
Encoded at 400kbps video - 96 kbps audio
Compressed filesize = 6,076 kbytes
Duration = 90 seconds
CALCULATION GIVES DATA RATE OF 527 kb/sec
(no alpha channel)
The only differences between the two vids is the alpha
channel and the duration. Somethings doesn't add up here.
Any clues?
Thanks
Simon

I've just partly answered my own question. Funny how writing
a post can help you think your problem through sometimes.
The issue is the alpha channel, which adds to the file size
thereby making the data rate "incorrect". In other words, the same
file encoded without the alpha channel provides the expected
results. I guess this changes my question to: How do I create
predicatable data rates when encoding using an alpha channel. I
could just estimate of course and see what comes out, but is there
a better way?
SImon.

What is the Data Rate of the Cache in Adobe Premiere CS6

Hi,
Trying to build a raid array to edit with and want to know how much speed i need for caching read/write drive for premiere and After Effects. I'm of the impression that the cache doesn't need more than a single 7200rpm drive (~120MB/s) but really i have no clue what the data rate that adobe caches to is or what the data rate to read is
so it's 2 questions
how fast does premiere write the cache? (i know this is system dependent but a ballpark figure would be good for say a sandy bridge i5 2500k system with a 2 raid 7200rpm drive)
and
what's the data rate to read the cache in a 1080 24p file?
also, when doing the final export does premiere/after effects read from the Cache or the original files or both?
thx,
Jayson
youtube.com/AWDEfilms

ok i've figured out the physics of this question.
The Cache Read data rate is always larger than the Cache Write data rate, because the computer would have to be rendering to Cache faster than realtime for the Write rate to be higher, which would make it unnecessary to render to cache in the 1st place. So I'm really only worried about the Cache read data rate. Does adobe have a paper that tells us what the data rate is for different sequences.
my 3 common workflows are
canon h.264 1080 24p
AVChd 1080 24p from my GH2 with a 44mb
and
r3d 5k epic footage 24p - (this is painful to edit )
anyone know where this info is?
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Jayson
youtube.com/AWDEfilms

What i smy actual data rate of FLV

I need to be able to confirm my data rate of my final FLV
file. I am using Sorenson Squeeze VP6 codec and have my video data
rate at 150kbps. When I play it back using Quicktime or SWF player
( on OSX ) it says my data rate is 1400kbps. But when I play it
back on windows XP using FLV Player from Applian and check the
properties it says that I am at the correct bit rate. What gives?
How do I double check that Sorenson has encoded my media at the
correct bit rate.
My basic settings in Sorenson are...
2 pass vbr at 150 for video and 48 for audio.
Thanks sooo much for your help!

ok i've figured out the physics of this question.
The Cache Read data rate is always larger than the Cache Write data rate, because the computer would have to be rendering to Cache faster than realtime for the Write rate to be higher, which would make it unnecessary to render to cache in the 1st place. So I'm really only worried about the Cache read data rate. Does adobe have a paper that tells us what the data rate is for different sequences.
my 3 common workflows are
canon h.264 1080 24p
AVChd 1080 24p from my GH2 with a 44mb
and
r3d 5k epic footage 24p - (this is painful to edit )
anyone know where this info is?
thx,
Jayson
youtube.com/AWDEfilms

H.264 data rate difference between local and distributed encode

Doing some testing today and noticed this curious behavior with compressor 3.5.1:
Set video encode for a 50 second 1080i uncompressed file to H.264 at 50000 kbps (50 mbps). Audio is 24 bit, 48khz stereo with no compression.
1. Sending the job to "This computer" for a local-only encode gives me a file size of 327 MB
2. Sending the same job to the same computer using distributed encoding gives me a file size of 211 MB
The data rate for the distributed encoded file is about 34 mbps, which isn't what was specified in the encode settings in Compressor. The data rate for the locally encoded file is about 52 mbps, which is what I would expect when the audio is taken into account.
Why the difference? Both encoded files are the same duration, so there aren't any missing frames. They both look good and play well but this is giving me cause for pause.
Also, another curious difference I noticed... The distributed file has the More Info fields populated with useful information in the Finder (dimensions, codecs, duration, channel count, total bit rate). The locally encoded file does not have this information.
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H.264 All-Intra Data Rates Significantly Higher

Does the built-in H.264 codec encode I-frame only files differently? I am trying to determine the optimal GOP length for high bitrate exports. Image quality seems to degrade, even in the I-frames, when using key frame distances greater than one.
After performing a series of tests to characterize the Adobe H.264 encoder, I discovered that exported files are significantly larger when key frame distance equals one frame (N=1). The average video data rate for a test file rendered with the Adobe H.264 encoder is as follows:
N=1 : 2.17 bpp : 24I
N=2 : 0.66 bpp : 12I + 12P
N=3 : 0.59 bpp : 8I + 8B + 8P
Note how the data rate drops 70% (from 2.17 to 0.66 bpp) even though 50% of the I-frames still exist when N=2. By comparison, here is the video data rate when exporting with QuickTime H.264:
N=1 : 0.89 bpp : 24I
N=2 : 0.70 bpp : 12I + 12P
N=3 : 0.64 bpp : 8I + 16P
The following chart shows data rates at key frame distances from 1-48 frames for Adobe H.264, QuickTime H.264 (via Adobe), QuickTime Pro, and Expression Encoder 4 Pro. Data rates are consistent among all encoders at GOP lengths greater than one. There is an anomoly with the Adobe H.264 codec compressing all-intra files.
The observed behavior occurs in all profiles, which were tested at Levels 4.1, 4.2, 5.0, and 5.1:
Image quality is better in the Adobe H.264 all-intraframe file, especially with respect to detail retention. The pictures below show sections of two consecutive frames magnified 400%. The file with N=2 is less accurate and contains noticeable blocking. Even the I-frames don't look as good in the files where N>1.
The test file was a seventeen second Premiere Pro sequence consisting of H.264, MPEG-2, and AE files with effects applied. Exports were rendered from the Premiere Pro timeline and from a V210 uncompressed 4:2:2 intermediate file of the sequence. The following settings were used:
Format: H.264
Width: 1280
Height: 720
Frame Rate: 24 fps
Field Order: Progressive
Aspect: Square Pixels (1.0)
TV Standard: NTSC
Profile: Baseline, Main, and High
Levels: 4.1, 4.2, 5.0, 5.1
Render at Maximum Bit Depth: Enabled
Bitrate Encoding: VBR, 2-Pass
Target Bitrate: Maximized for each Profile/Level
Maximum Bitrate: Maximized for each Profile/Level
Key Frame Distance: 1, 2, 3, 4, 5, 6, 7, 8, 12, 24, 48
Use Maximum Render Quality: Enabled
Multiplexer: MP4
Stream Capability: Standard
Software:
Adobe Media Encoder CS6 Creative Cloud v6.0.3.1 (64-bit)
Premiere Pro CS6 Creative Cloud v6.0.3
Windows 7 SP1
QuickTime Pro for Windows v7.6.9 (1680.9)
MediaInfo 0.7.62 (for GOP and data rate information)

I think the short answer is yes,
a h.264 encoder does I-frame only differently. I frames are complete expressions of a picture with no temporal compression information.
P frames use _P_redictive information. IE information from prior frames.
B frames use _B_i-directional predictive frame information.
h.264 gets the majority of it's bit saving from use of B and P frames. When you do I-frame only you only get the block compression and none of the advantages of P and B frames. Thus the GOP N=1 doesn't get very good bit's per pixel.
Having said all that I do find your comment...
Profitic wrote:
Note how the data rate drops 70% (from 2.17 to 0.66 bpp) even though 50% of the I-frames still exist when N=2. By comparison, here is the video data rate when exporting with QuickTime H.264:
... very interesting. Indeed, why is the datarate 70% less when it should at best be 50% for GOP N=2. 50% less should be the same I-frame information plus 0 bytes for the B frame between them. (GOP = I,B,I). Any more than that and it is throwing away bits from the I-frame. So, this seems to be to be a ratecontrol bug.
http://en.wikipedia.org/wiki/Group_of_pictures
"The GOP structure is often referred by two numbers, for example, M=3, N=12. The first number tells the distance between two anchor frames (I or P): it is the GOP size. The second one tells the distance between two full images (I-frames): it is the GOP length. For the example M=3, N=12, the GOP structure is IBBPBBPBBPBBI. Instead of the M parameter the maximal count of B-frames between two consecutive anchor frames can be used."

In Aperture 3.4 Export Slideshow to a video, what are the actual Data Rates used for "Best", "High", ... "Least" quality for a given resolution?

My Photo website host (SmugMug) converts uploaded video files at a specific Data Rate in Mbps before installing them. I would like to compress my slideshow video file to the same rate before I upload it to reduce file size and upload time. When I choose the "Custom" setting for an Export, I can choose 1 of the 5 Quality choices and see the estimated file size. But, I cannot know what the actual Data Rate is until after I wait a long time to export the slideshow (hours for a long slideshow) and then examine the resulting file in QuickTime Player's Inspector.

I ran a few tests using a short slideshow (16 images, 1:23 mins/secs) at 1,728 x 1,080 resolution to find out the bit rates for various quality level choices.
Export setting              Quality          Resulting bit rate          File Size
HD 1080p                    default                20.68 Mbps              214.8 MBytes
Custom                       Best                   20.49                       212.8
Custom                       High                     6.25                         65.0
Custom                       Medium                3.97                         41.3
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I have installed MPEG StreamClip that will let me convert an exported Aperture slideshow video file, and StreamClip allows me to choose a specific bit rate in Mbps. But, I would prefer not having to do a 2 step process (Export from Aperture, then convert in StreamClip).

What is data rate consumption for iPods?

Since getting two iPod Touches, an iPhone 4, and an iPhone 5, our data consumption has skyrocketed. We are allotted 250GB of data use each month and we are currently sitting at 330GB with a week left.
I checked with netflix and the setting is at .3 (the lowest download rate). No one is home for 8 hours during the day, and we watch netflix about 3 times a week for about 2 to 3 hours.
we don't download movies and computer use is minimal.
We averaged about 120GB of data per month with the IP4 and 1 iPod, now it's skyrocketing.
What can I check on the devices to lower the download data rates?
Yes, our router is locked out, so no one is stealing bandwidth.
Thanks for any suggestions.

Look into this app - it seems written for you:
https://itunes.apple.com/us/app/data-monitor/id495999810

How do I find out what is the current data rate on my wifi card?

I have a macbook pro running OSX 10.8.2. When I go to system profiler I see that the card is in 802.11n mode, but how do I find out the current rate? There is a 'Transmit Rate' parameter but there is no unit next to it.

The data rate depends on if it is using the 2.4 GHz band or the 5 GHz band, both are possible with n-protocol unless you have limited your wireless to only one band. The data rate in 5 GHz is double that in 2.4 GHz. Also, you have to know what the protocol of the network is, the AirPort card can only transmit at the rate of the network, so if you are on a g-protocol router, that is the fastest rate you can see.
And then interference, attenuation, etc. will drop that rate.

Ipad 2 video data rate. Whats the maximum data rate it can play back?

I'm creating a video file I want to play in 1920 x 1080 on the ipad 2 and not sure what the maximum data rate should be.

Frankiedude wrote:
I'm creating a video file I want to play in 1920 x 1080 on the ipad 2 and not sure what the maximum data rate should be.
Depends upon the format of the video. See:
http://www.apple.com/ipad/specs/

Data rate when creating Quicktime h.264: difference between download and streaming ?

I've got a question on data rate setting when creating a quicktime movie with h.264 codec:
In the Compression settings dialog I can restrict the data rate to a certain value (e.g. in my case I use 20.000 kbit/s for creating a HD1080i movie).
There is an additional drop box "Optimized for" where I can select between "download", "streaming" and some other value.
Is anybody aware of the exact meaning of these settings ? My impression is, that using "download" I set the average bit-rate, allowing much higher bit-rates in peaks, while "streaming" sets a maximum bit-rate. Is that correct ? or are any other parameters affected by this setting ?
I now discovered, that the output file when using "streaming" with restriction of 20.000 kbit/s leads to a file with average bitrate of only approx 17.000 kbit/s (while it's more or less exactly 20.000 when using the "download" setting). Does that mean, that the overall quality of my output file would be worse ? or would only peak rates be affected (e.g. scenes with a lot of movement) and the overall quality remains the same ?
Happy to learn if anyone has any experiences / best practices on this topic.

Restrict isn't, it seems, a hard limit. When I specify 18Mbps it seems to run up to 21Mbps. But, that's fine since it's certainly isn't excessive and if I really cared I could set it at 15Mbps.
I suspect it might be more accurate with 2-pass. Also, i never ever use the Apple codec. i use x264 which allows more encoding tools. And, even it is not a super good H.264 encoder.
Using rates under 2400Mbps is IMHO asking for the near impossible for good quality SD video.

Canon 5D Mark II data rate drop

Trying to work in the original source format H.264 with clips from Canon 5D Mark II in FCP to show off the excellent resolution of the cam's video format.
Everything looks great in the exported self-contained QT movie (aka FCP Movie) of video clips only--data rate nice and high at 42.xx mbits/sec. Then I add text clips, and the data rate (and resulting footage quality) plummets to 20.xx mbits/sec or lower depending upon how much text I've added and whether the text overlays footage clips.
Sequences where I've not added any text retain the original data rate of the source files (42.xx when played back in QT) and look fantastic. But those with text get as blocky as the data rate drop involved.
Any idea why FCP is doing this to these Canon 5D H.264 sequences when text is added??
Mary Lynn

Yes, thank you both for your responses. Quite familiar with ProRes conversion workflows and H.264 delivery, etc.
What we are trying to do is show clients precisely what the footage looks like right out of the Canon 5D, which is pretty fantastic. FCP will actually create a sequence that matches the 40 mbits/sec long GOP H.264 right out of the digital SLR cam, and will maintain the data rate and great quality in exported self-contained QT movies consisting of hard cuts between multiple clips...that is until text is added.
But it looks like for now we'll just have to transcode and show clients that instead. (Although hopefully future versions of FCP will allow us to edit Canon's 5D variant of H.264 natively!?)
Thank you again for your responses!
ML

What chokes H.264 footage: data rate or video dimensions?

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