Bit rate question

I have always managed to fit 65 minutes on a DVD disc with no problems but now need to get 75 mins on to a disc. I have never really got my head round bitrate conversion tables - In DVDSP2 I normally use Target bitrate - 6, Max Bitrate - 8 and motion estimation - best. if I lower the Target bitrate to say 5 instead of 6 will this allow me to get the extra footage on the disc even though quality may diminish?
There is normaly a centimetre left unburned on the disc. Any suggestions appreciated.

It can be a headache John, but fortunately there are tools to help with the calculations.
Check out any number of bitrate calculators on the web. One I use is over at http://www.wiredinc.com/bitrate.php, but you could also go to my .mac space and download a small app called 'Mr BitBudget'. This will give you a pretty accurate bitrate target according to the type of disc you are writing to, the video length, the bitrate of your audio and the existence (or not) of subtitles, etc.
In your case, Mr B reports that if you are using AC3 files for the audio (which have a bitrate of 192kbps) then for 75 minutes of video your bitrate needs to be no more than 7.8MBPS for a DVD-R. For compatibility reasons, set the maximum to 7.4MBPS and the lower setting at something suitable for the kind of footage that you are using (i.e. at 4MBPS for still interview type stuff, 5 for general shots, 6 for faster action, panning, zooming, etc).
However, if you are using .aiff audio then this max bitrate falls to nearer 6.5MBPS... so adjust the lower setting in your encoder accordingly to get the encode that you need. As long as you don't have any ROM content or subtitles then this will be about right for you.
Incidentally, different encoders work in different ways and what you can achieve in terms of quality at 6.5MBPS in DVDSP is far exceeded by using BitVice at the same settings, or MegaPEG.X. It is well worth thinking about using a different encoder if you need to squeeze the best result out at the lowest bitrate (don't forget, higher bitrates produce larger files). Whilst alternate encoders cost money, if you are doing a lot of different authoring jobs investing in one will pay you back many times over.

Similar Messages

Export Settings - Minimum Bit Rate Question (MPEG2-DVD)

Hi,
Curious...just came over recently from FCP and I don't remember Compressor giving me an option to adjust the MINIMUM bit rate when exporting HD projects for DVD. I figured I'd just leave it where the preset has it (at 2.8mbps minimum)...BUT...then I hovered over it and saw an interesting popup/explanation of what it does which kind of confuses me. It says:
Higher values set a higher minimum quality, but reduce quality of more difficult scenes.
The first part makes sense so I figured I'd raise it...but then the second part makes me think I should keep it low. Sort of confuses me. Any thoughts??? FYI: My projects are Weddings with a fair amount of action, etc.
Normally, these are my settings depending unless I can't fit the project onto the disc in which case I adjust:
DVD
CBR at 7.5mbps
...or...
VBR 2pass
Target Bit Rate: About 6.8 or 7mbps
Max Bit Rate: Usually 8mbps
BLURAY
VBR 2pass
Target Bit Rate: 25mbps
Max Bit Rate: 30mbps
Unless someone tells me that I should raise these settings higher for better quality output (if the project size allows of course) these are what I've been using to get maximum quality out of my videos without jepordizing playback due to bit rate max for each media (which I think I read was 10mb and 40 or 50mbps respectively. I was just thrown by the minimum bit rate description above.
Thank you in advance for your help!

The whole notion of a minimum bitrate is crazy unless you have specific broadcast requirements that require you to pad out video to keep the connection alive.
If the encoder can express the image with zero loss in less than the minimum bitrate why would you pad it with zeros to get the bitrate high enough to meet the min?
The idea of a nominal/average bitrate is easy to understand.
The Maximum bitrate is often misunderstood though.
On some encoders the max rate sets the wiggle room (max - average) that can be used if there is a burst of required information.
On other encoders it sets the maximum rate at which the video buffer is allowed to fill as per the specifications. eg Blu-ray is capped at 40Mbps. The Video encode itself MAY EXCEED THAT 40Mbps for a split second but will only LOAD into the video buffer at up to 40Mbps.
For example, if you set constant bitrate at 20Mbps and no Maximum rate when the video first starts loading from the blu-ray disc to the video buffer it loads faster than the blu-ray maximum of 40Mbps. Thus you MUST have a maximum rate defined (for blu-ray compliance) even though it's a constant bitrate. Some encoders do this for you but some leave it up to the user to get right (and thus should provide a max slider and constant slider to set both).
Jeff- absolutely agree. It's very rare that you need to use all 40Mbps available to you. 20 and 30 can look great (depending on the detail in the sceen and how much motion there is).
VBR 2-pass does have value if you're trying to get down to lower rates like 10Mbps to fit a long title on a disc. If you don't action shots with sceen cuts will leave artifacts as they are bit starved.
I'm actually a big fan of Constant _Quality_ (CQ) vs CBR or VBR. You then know what quality you're going to get on every frame and from experience will know how big it will come out to be. CQ is also considerably faster to render because you have no rate control computations to do. x264pro has a CQ option for this very reason.
hope that helps.

Compressor bit rate question

I put together a 28 minute bike video and I am having some dvd playback issuses (for some dvd players, not all). For some reason the video pauses and skips in the middle of the video. Is there a recommended bit rate to export using compressor? I just export with the default setting on 120 min, 4.0 - 7.5 bit rate at best quality. I read somewhere you take a risk if your bit rate is over 7.0. Any thoughts?

When we first started supplying DVDs to the public we had quite a few issues with some dvds not being compatible. It was never very logical but the rule was that the more expensive the machine the more likely it would not play. In fact some clients actually prefaced their enquiry with the words "I am afraid it was a very expensive machine and we have been told it can be a problem"! Often also they were Sonys.
However I have to say that we have not had this problem for a couple of years now and had just assumed that everything is much more compatible now. Many people who watch Hollywood movies only, do sometimes get problems when they try to watch a copied movie for the first time - remember the process is different (and also that they do damage a little more easily than the pressed ones). It is always hard to convince someone who has watched movies without problem that it may be their machine. Nine times out of ten they would send them back and they played ok on numerous machines back here and we would send them another and it would be fine. Who said this was a science?? Your only other alternative might be to play out into a stand alone recorder and try that but you will lose your menu structure.
Pete Snowdon

Blu-Ray bit rate (and other questions)

Hi, just getting ready to try out my new blu-ray burner and I had a couple quick questions regarding outputting via compressor, thanks for any help and advice:
1) What's the recommended average and max bit rate assuming file size isn't an issue?
2) Can I put multiple videos on one blu-ray? From what I can tell it's only one per disk...
3) The blu-ray template wants audio and video from one source, correct? Or can I drop in a quicktime video and a separate audio track? (For instance, I have a surround sound mix that was done elsewhere while the video was edited and output from an Avid)
4) Will compressor accept Avid DnxHD quicktimes?

I assume you mean to create a BD with Compressor.
1. 34mbps, if I remember, is the max. Just let Compressor calculate the average and max. With a good source, an average above 24mbps won't make a difference of quality, in my opinion.
2. No; you have to have a single movie all assembled in FCP first. But you can use chapter makers to mark multiple original movies.
3. One source only, correct.
4. I don't know.

2 Questions - Low Bit rate output. Low frames per second FPS, HELP! Live show sucked!

I thought I had all of my settings set for a stream using FMLE running through stickam. Everything was looking good but when we went live our bit rate output went down below 100kbs. I had set it for high kbs but allowed it to drop size to keep frame rate. As you can imagine our video stream went from really good looking to choppy and almost freeze frame half the time. I have no idea what I did wrong. Is it my Cable Internet? My modem? I will say that I ran a speedtest.net test and although the download looked abnormally low I had 1.6Mbs upload which I thought should be sufficient? I'm not sure what to do.
2nd question. I set FPS frame rate at 25fps but the output only allowed 15fps to the live stream. What is causing this? Is this a default number? It didn't seem what I set the frame rate at, the output was at 15fps. I saw ways to change the fps on the input but nothing on the output. What is the deal here?
So... to recap. How do I keep the bit rates high and constant on a stream and how do I increase my fps on a stream. Or, to make it real easy, how do I get the best video stream picture that is not choppy or freeze frame. Our show is now starting to be sponsored by entities and I can't have bad looking shows. Can anybody lead me in the right direction?

Whats your Encoding machine's configuration? I feel a low configuration machine can cause choppy streams.
Did you try with any other video source?
I feel you have enough bandwidth to stream.

Controlling output video bit rate in FCPX

I ran into a problem: I created a mp4 file with Share/Export File… (settings: Computer, H.264 Faster Encode, 1920x1080 - edited from an HD camera): its video always freezes at a definite point when played on my BD Player connected to my HDTV through HDMI (audio instead continues on the frozen image).
It seem that the issue is a sudden video bit rate pick of almost 50 Mbps while its average is around 20-30 Mbps. It is not clear to me if this freeze is caused by the BD Player or by the HDTV not being able to handle such pick.
As a test I used Compressor to control the output bit rate (settings: average 20 Mbps and pick 25 Mbps) and this seems to fix the problem. To be more certain I should do more tests, but I'm confident I found a possible solution.
I'd like to know if there is a way in FCPX to control such picks (without using Compressor), either in the Share commands (but it seems to me that they don't provide enough setting controls) or in the timeline. By watching the Video Scopes I can see a quite strong signal in the area where the output file has the bit rate pick. But I don't know any way to have a measure useful to identify them before sharing and avoid a trial and error approach...
Piero
Below the critical point...

Tried to upload a PDF instead of PNG, but no luck. The picture shows a quite standard (I'd say...) image but with highly dense graphic of Y' component in the Y'CbCr Parade (in the limits of 0-100 IRE): much more dense than most images in the rest of the movie. So I assume this might mean a higher bit rate... but it's just an assumption.
Let me summarize my tests:
1st test: FCPX: Share/Export File.. (settings: Computer, H.264 Faster Encode, 1920x1080)
- copied the .mp4 file to USB drive
- USB drive into a BD player connected to HDTV through HDMI >> freezing effect
2nd test: FCPX: Send to Compressor - Compressor: Create Blu-Ray Disk (on Hard Drive) and Video Job with standard Video settings (Automatically select bit rates = ON)
- Played the .img disk with "Mac Blu-Ray Player" on my iMac >> same freezing effect in same position as before on HDTV
3rd test: FCPX: Send to Compressor - Compressor: Create Blu-Ray Disk (on Hard Drive) and Video Job with customized Video settings: Automatically select bit rates = OFF - Average = 20 Mbps - Maximum = 25 Mbps
- Played the .img disk with "Mac Blu-Ray Player" on my iMac >> NO MORE freezing effect (and smaller file by 30%)
I might do more tests (mainly on my HDTV) but I believe the point is the bit rate... and the only way to control it is by using Compressor.
So now my question: is there a color setting that helps in controlling such situation ? e.g. lower saturation, or lower exposure, maybe in mid tones or highlights, or what ?
Thanks so much for your help
Piero

Best Bit Rate for Better sound

I’m new to the iTunes/iPod thing. A friend told me that he re-sets the bit rate from the default of 128 kpbs to the top of 320 kbps for better quality. [He plays everything off of his computer which is wired to speakers throughout his house and does not travel or drive much so hardly uses his iPod.] I played around a tad with the various rates on the same album and found that a fairly short one used 34.9 MB at 128 kbps, 52.1 MB at 192 kbps, 60.8 MB at 224 kbps and 86.6 MB at 340 kbps. Another friend told me that he noticed a big difference when he played a song off his iPod through his several thousand dollar system if it was imported at 128 kbps. While hard disc space is cheap and I would simply opt for the higher quality setting, the iPods are not so big when one almost triples the file size.
I tried to figure out what the max bit rates in the CDs are so that could guide the max import rate, but I could not and that question may make no sense at all anyway.
What is the max that a human can notice the difference at and what have folks found to be the best balance between sound quality and storage space?
Thanks for your help.
PC Windows XP

Monty, this is really going to be up to your ears to decide. All I can tell you is my experience during the 2+ years of owning an iPod. I initially thought AAC @ 128 was satisfactory. I then started experimenting with various bitrates, but kept the AAC format. I decided that 192 was a discernible improvement over the 128. Not to go into a lot of detail, but I, quite by accident, had one album download at 256 & thought, "Wow, this is unbelievably better sound, even over inexpensive computer speakers." At that point, I started importing everything in AAC @ 256 VBR which I feel is pretty darn close to CD quality sound. I have a 60GB iPod that I'm willing to sacrifice some capacity in order to ensure the best audio quality I can. This is also why I do not buy frequently from the iTunes store as I do not feel the 128 downloads are the best quality. I buy & my own CD's, now, to insure good quality. I will by the occasional song from the store when I do not care to buy the whole CD. Hope this helps!

Using the "Convert higher bit rate songs to 128 kbps AAC" feature...

I recently discovered the "Convert higher bit rate songs to 128 kbps AAC" feature and used it to copy my entire 70 GB music library to my 64GB iPad. The music library now occupies only 45 GB. Awesome!!!
Unfortunately, the whole process took well over 24++ hours on my quad core Windows 7 computer (takes about 6 seconds per track). Questions:
1. Is it possible to speed up the process? Even though I am using iTunes 64-bit version, it seems that at no point is more than a single core being used at 33%. Seems to me like overall 8% of the CPU (33% / 4) capacity is being used for the conversion and 92% is being left idle. Is this just bad programming or is there anything I can do to speed up the process? Others see similar problems?
2. Now I have already started dreading the day, I need to restore my iPad (e.g., when OS version 4 becomes available). I would hate to have to do this process all over again. Should I need to restore my iPad, is there anyway I can force iTunes to back up the 128-bit AAC versions on my computer and restore it up from there?
Any insights into both these questions will be deeply appreciated.
Cheers,

ed2345 wrote:
malus_domestica wrote:
Thanks for the response.
So, I am wondering why iTunes uses only 8% of the processor power in converting the songs.
Possible reasons not to grab more of the CPU power (1) maybe the process is I/O bound due to all the writing, and is not processor limited? (2) since conversion is almost always a background program, and the user will typically have other things going on, maybe it intentionally limits CPU use?
I ran a few quick experiments (out of curiosity) and think the answer is #2. No apparent technical reason but potentially a limitation introduced by Apple's engineers to maintain a good user experience (for some people at least). I fired up 4 instances of dbpoweramp and ran multiple conversions and found that the process goes faster than what iTunes can do by an order of magnitude. With luck, someday Apple will have an option for users to select how much of processor bandwidth to be allocated for the conversion.

How do I change the bit rate for dls?? How times can I download one song??

I'm new to iTunes. I already downloaded 3 songs when I realized that the default bit rate is 128Kbps. I tried changing the bit rate to 192Kbps with a (Variable Bit Rate) checked.....unfortunately when I downloaded the next 2 songs the bit rate turned out to be the same.
Do I have to restart Windows or iTunes before downloading again?
And now that I have 5 songs with a lower br than I wanted... in order for me to have(download) the song at the higher bit rate...Is it possible to download one song more than once?
Thanx.

You have no choice as to bit rate when purchasing from the iTunes Music Store. The official bit rate of all tracks there is 128 kbps (a very few have been reported to be at higher rates, but that's not a choice you can make, it's how the track was encoded by the record company). The setting in the iTunes Importing preference is for tracks you import from CDs only and has no effect on iTMS purchases.
Is it possible to download one song more than once?
No. Except in extraordinary circumstances, the iTMS allows only one download per purchase.
Forum Tip: Since you're new here, you've probably not discovered the Search feature available on every Discussions page, but next time, it might save you time (and everyone else from having to answer the same question multiple times) if you search a couple of ways for a topic before you post a question.
Regards.

Sample & bit rate

I have a two part question:
1) I have a Presonus Firebox that allows me to record up to 24 bit/96k. I am wonder if I should take advantage of this and use those settings in audio midi setup for when I record into GrarageBand? Is it worth the extra file size? Is there a noticeable quality gain? Will 96k work with GB?
2) I know GB is only 16 bit and that CD's that it will be mixed to are at 16 bit/44.1 kHz. But what about if I record a song in GB at 24 bit/96k, mix down to iTunes, and put it on my ipod as an AIFF will the increased quality show up there? What about on an Audio DVD made from itunes with iDVD.
Thanks for any info and/or opinions,
Paul

Not that it's relevant in the context of GarageBand, but it might be useful to clarify the effect of sample rate and bit depth.
The sample rate affects the frequency response. it is mathematically impossible for a sampling system to correctly render any frequency at or above half the sampling rate (trying to do so produces false frequencies - 'birdies ' - known as aliasing). 44.1kHz effectively limits your frequency response to about 21 kHz, 48kHz to about 23 kHz, and so on.
The bit depth affects the noise floor: 16-bit gives a theoretical noise floor of about -90dB below peak: 24-bit gives a theoretical noise floor of about -138dB below peak. -90 is pretty well inaudible: but remember that when adding tracks together the noise, being random, is added (3dB per track if they are the same level when mixed - of course the peak level increases too). The digital noise, if it becomes audible, is far more annoying in its sound than good old-fashioned tape hiss.
In practice, GB's restriction to 44.1/16-bit isn't really that much of a problem: of course 96/24 would be better, but you gets what you paid for!
Incidentally, don't confuse bit depth with bit-rate, which is a combination of the sampling rate and the bit depth, and is fixed for uncompressed files: but of course as you compress files with MP3 or similar you reduce the bit-rate by leaving out information, even though the sampling rate is the same.

Audio bit rate (kbps) and file size balance

I'm new to Flash, and I'm trying to decide how to set the bit
rate (kbps) for my audio files.
I'm creating PowperPoint-like presentations with voice audio.
You can see what I'm doing at
http://preparatorychemistry.com/Bishop_Audio_Book.htm
I first decided on 16 kbps, but I'm not happy with how it
sounds, especially through headphones connected to the computer. My
presentations, of course, sound better with higher bit rates, but
file sizes roughly double for each doubling of the bit rate. At 16
kbps, my files range from 1-3 MB, so for 32 kbps (which I'm leaning
toward now), they are 2-6 MB. My questions are
What's the concensus on the best bit rate for Internet sound
files, especially voice?
How important is it to minimize files size? The files are
already large enough so that dial-up folks will probably not listen
to them, and even the larger files seem to download fast enough
with my cable connection.
Thanks for the help.
Mark

Chemistry guy wrote:
> I'm new to Flash, and I'm trying to decide how to set
the bit rate (kbps) for
> my audio files.
>
> I'm creating PowperPoint-like presentations with voice
audio. You can see what
> I'm doing at
>
>
http://preparatorychemistry.com/Bishop_Audio_Book.htm
>
> I first decided on 16 kbps, but I'm not happy with how
it sounds, especially
> through headphones connected to the computer. My
presentations, of course,
> sound better with higher bit rates, but file sizes
roughly double for each
> doubling of the bit rate. At 16 kbps, my files range
from 1-3 MB, so for 32
> kbps (which I'm leaning toward now), they are 2-6 MB. My
questions are
>
> What's the concensus on the best bit rate for Internet
sound files, especially
> voice?
The best is the import high quality sound in wav format. Than
in library you can
play around with m3p compression changing the rates and all.
Checking the quality
versus the file size and find one that suit your needs. There
is no BEST format to
import. Every single fill have individual setting. It's all
depends on the sound.
Like, in case of voice. Very different to other sounds.
Save it as ADPCM (adaptive pulse code modulation) or Mp3
9kbps as your second choice.
Also take note that STREAM always lower down the quality , it
suppose to load fast so flash reduce
it enormously , usually sound like pure crap, go to library
(CTRL L to open) right click your sound
and go to properties, adjust the compression and type of
audio format to find best size and quality...
> How important is it to minimize files size? The files
are already large enough
> so that dial-up folks will probably not listen to them,
and even the larger
> files seem to download fast enough with my cable
connection.
You would be surprised. I was doing voice overs two or 3
weeks ago for a client.
Needed 5 sounds , up to two minutes each, for different
slides. Ranging from 2.5 MB
to 2.9 MB per file.
After compressing all of them, I had 5 sounds in very good
quality of total size 1.4 MB
Best Regards
Urami
<urami>
If you want to mail me - DO NOT LAUGH AT MY ADDRESS
</urami>

How to determine the bit rate with button over video subtitles?

I have a project where I've got several questions that come up on the screen. The DVD is subtitled in 14 languages, so depending on the language chosen, it will show the question in the proper language along with navigation buttons to go to the next question or track.
The problem is this: I added several new questions that each have a black only video that runs about 1min with 14 subtitle tracks made from photoshop psds. When I try to build, it fails saying "bit rate too high." When I removed all but 5 of the subtitle tracks, then it would build. I came up with a workaround, but then hit the limit of 99 tracks, menus or stories on a DVD.
I went back and tried combining all 3 questions in to one slide, but now with more information on the psd, it will only allow 3 subtitle tracks before it reaches the max bit rate.
How does it determine the bit rate? What can I do to lower the rate? I tried compressing the video at the lowest bitrate, but it didn't' help. I tried changing the psds to much smaller jpg files, but it didn't change anything. If anyone has any suggestions, please let me know!
Thanks.

CS,
Almost all DVD SP Tracks should first be completely constructed in a Sequence in FCP, the markers placed there, and then everything encoded into a single Mpeg 2 clip with matching length audio (even if just low bit rate AC3 silent audio, as the case may be, because all Mpeg 2 clips in the Title domain should be accompanied by an audio stream), and then imported into DVD SP.
Lay your subtitles under that and see what happens.
Take care,
Trai
TFDVD Research Labs

Streaming multi bit rate and single bit rate

I'm trying to simplify my setup. Sometimes I need to stream multi bit rate and sometimes I need to stream single bit rate. This is due to the internet connections I'm sending from sometimes have poor upstream and multi-bit rate is too much bandwidth to send... So.... We resort to single bitrate. As I understand my encoder and server settings are different for each of these... I created a single and multi-bitrate profile for Adobe Media Encoder. That was simple enough. My question/concern is in regards the server settings. I would like to have a server setting for multi-bitrate and a setting for single bit rate. My goal is to void making changes on the server. I simply want to load the desired Adobe Media Encoder Profile. So, do I need to create a dedicated event for single bitrate? Below is the syntax I send to my server from Adobe Live Encoder. Instead of using 'liveevent' for my event would I just give it a different name? Does this stand true for my .m3u8 files? I'm confused to how to name differnet event/streams....
livestream%i?adbe-live-event=liveevent&adbe-record-mode=record

Hi,
When you use a setting like: livestream%i?adbe-live-event=liveevent then the encoder expects multibitrate streams (the %i is replaced by a number so the streams published will be livestream1, livestream2 and livestream3). You cannot use the same setting in the encoder for single stream. Instead you'll have to use livestream?adbe-live-event=<event_name>. You could create a new event under the same application.
Hope this helps. Let me know if you have any other queries.
Thanks,
Apurva

Bit rate standards for Compressing video for Captivate

I have been trying to decide whether rto use constant bit rate or a variable bit rate when compressing my video to embed in Captivate.
I have been told by Connect support that a constant bit rate is better for deploying video in Presenter but I am wondering if anyone has information as whether that is also true for Captivate. We are using captive as a means to offer a series of video question and answer sequence for a client of ours, and I am interested in getting the best quality with the smoothest performance in a progressive download flv format
For a simple talking head I am tempted to use a variable bit rate but, I cannot find anything in the seaces I have made that talk about the spec or any pros an cons to that quetsion for Captivate.
Doee anyone have any expereince with that?

I have always used constant bitrate for videos imported into Captivate and that has worked fine. However, I never tried using variable bit rate so I don't know if it will work better or worse.
My guess is that it would be better to go with constant bitrate though because Captivate do have some funny issues with FLV's sometimes and it's probably better not to "stress" captivate ;o)
/Michael
Visit my Captivate blog with tips & tricks, tutorials and Widgets.

Compressor: setting max bit rate for VBR audio

Hi,
I am using Compressor 3 to transcode DV to H.264. I want to encode the audio to AAC VBR wtih a max bitrate of 256. Under the Settings tab, under audio, for VBR there is a slider from good to best. what does this mean in terms of max bit rates? How can you use this slider in a meaninful way?
There is a setting for Average Bit Rate, where you can select a value. do we konw what the max bit rate would be?
thanks
dan

Good question about the slider…and I really don't know the answer. Why don't you try a test: crank it to one extreme and then the other with a representative source file and see what impact it actually makes on the properties of the respective output files.
Good luck.
Russ

Bit rate question

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