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Lossy Audio Compression => AAC => AAC - Tech => Topic started by: paperskyline on 2013-10-16 13:42:46

Title: Encoding with True VBR
Post by: paperskyline on 2013-10-16 13:42:46
Recently I have been encoding music with True VBR using foobar & dbpoweramp. everything has been fine so bar, but the bitrate in itunes does not appear as "256kbps".
It appears as " 283, 271, 299, 301,,...etc."
So my question is how does the iTunes Store encode their music in True VBR, but appears as "256kbps" when displayed in iTunes?

My Settings:
dbpoweramp: -V 118 -q2 -r keep -n -R -S -o [outfile] -
foobar: --tvbr 118 --highest - %d

I even tried using "110, 113, 115"

Please try to be as much precise as possible and do not digress from the topic
Title: Encoding with True VBR
Post by: 2Bdecided on 2013-10-16 14:23:14
Please try to be as much precise as possible and do not digress from the topic

Yes SIR!

http://wiki.hydrogenaudio.org/index.php?ti...ariable_Bitrate (http://wiki.hydrogenaudio.org/index.php?title=Variable_Bitrate)
http://wiki.hydrogenaudio.org/index.php?ti...onstant_Bitrate (http://wiki.hydrogenaudio.org/index.php?title=Constant_Bitrate)

Why do you believe iTunes uses VBR when it reports CBR?

Why would you expect VBR to deliver a constant bitrate?
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-16 15:15:13
Please try to be as much precise as possible and do not digress from the topic

Yes SIR!

http://wiki.hydrogenaudio.org/index.php?ti...ariable_Bitrate (http://wiki.hydrogenaudio.org/index.php?title=Variable_Bitrate)
http://wiki.hydrogenaudio.org/index.php?ti...onstant_Bitrate (http://wiki.hydrogenaudio.org/index.php?title=Constant_Bitrate)

Why do you believe iTunes uses VBR when it reports CBR?

Why would you expect VBR to deliver a constant bitrate?

well as far as i have read in this site, itunes store music is encoded in True VBR and previously it used to be encoded with "-CVBR 256 -q2".
i even tried to get the exact 256kbps bitrate by using "-CVBR 256 -q2" , but no result
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-16 15:19:08
this topic shows what i mean

http://www.hydrogenaudio.org/forums/index....howtopic=102589 (http://www.hydrogenaudio.org/forums/index.php?showtopic=102589)
Title: Encoding with True VBR
Post by: marc2003 on 2013-10-16 15:50:22
but appears as "256kbps" when displayed in iTunes?


itunes isn't displaying the real bitrate. that screenshot of mine in the other thread is reporting 256kbps but looking at that same file in foobar, it's 260kbps. if i look at all my other itunes store purchases, they vary between 249 and 285kbps.

try looking at your store purchases in foobar.
Title: Encoding with True VBR
Post by: eahm on 2013-10-16 15:51:18
well as far as i have read in this site, itunes store music is encoded in True VBR and previously it used to be encoded with "-CVBR 256 -q2".
i even tried to get the exact 256kbps bitrate by using "-CVBR 256 -q2" , but no result

You just said you read here that iTunes encodes in TVBR then you show a CVBR command, you need to acknowledge there is a difference between the two first.

Like paperskyline quoted from the qaac website, iTunes uses "-v256 -q2" (CVBR not TVBR) for iTunes Plus setting and "-a128 -q1" (ABR) for iTunes High Quality setting.
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-16 17:26:41
what exactly is the difference in these settins? and which is better

-V 118 -q1
-V 118 -q2

-q1 or -q2?
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-16 17:31:03
https://dl.dropboxusercontent.com/u/2280132...tember/qaac.png (https://dl.dropboxusercontent.com/u/22801321/2013/september/qaac.png)

this image clearly shows that the file was encoded using CVBR 256kbps
Title: Encoding with True VBR
Post by: eahm on 2013-10-16 17:31:45
Quote
Like paperskyline quoted

I meant testyou here: http://www.hydrogenaudio.org/forums/index....st&p=844379 (http://www.hydrogenaudio.org/forums/index.php?s=&showtopic=102589&view=findpost&p=844379)


From https://github.com/nu774/qaac/wiki/Encoder-configuration (https://github.com/nu774/qaac/wiki/Encoder-configuration):

Quote
--quality is an another option concerning quality, and you might be confused. This is the same with the previous dialog's "Quality". This option controls not file size, but the trade off between encoding speed/quality. Bigger value means higher quality, and slower encoding speed. By default, qaac uses 2 (best quality, slowest speed). Usually, higher -q setting seems to produce smaller file.
Title: Encoding with True VBR
Post by: LifeWOutMilk on 2013-10-16 17:46:36
what exactly is the difference in these settins? and which is better

-V 118 -q1
-V 118 -q2

-q1 or -q2?



From https://github.com/nu774/qaac/wiki/Encoder-configuration (https://github.com/nu774/qaac/wiki/Encoder-configuration)
Quote
--quality is an another option concerning quality, and you might be confused. This is the same with the previous dialog's "Quality". This option controls not file size, but the trade off between encoding speed/quality. Bigger value means higher quality, and slower encoding speed. By default, qaac uses 2 (best quality, slowest speed). Usually, higher -q setting seems to produce smaller file.
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-16 18:04:20
http://www.hydrogenaudio.org/forums/index....mp;#entry844379 (http://www.hydrogenaudio.org/forums/index.php?showtopic=102589&st=0&p=844379&#entry844379)


if that says the itunes settings are " -v256 -q2 "

then how can it be this
https://dl.dropboxusercontent.com/u/2280132...tember/qaac.png (https://dl.dropboxusercontent.com/u/22801321/2013/september/qaac.png)
Title: Encoding with True VBR
Post by: marc2003 on 2013-10-16 18:38:43
you're looking at what QAAC has written to the tool field. the reason it says 256kbps is because that is the target bitrate. look to the left and you'll see the real bitrate for that particular file is 262kbps.

itunes does confuse things further as i already explained above. looking at the "real" bitrate in the "get info" dialog always reports 256kbps for itunes store files even though their bitrates are VBR.

this screenshot shows an EP purchased from the itunes store. note how that itunes is reporting 256kbps for all of them. but when i load the same files in foobar, they are clearly VBR.

(https://dl.dropboxusercontent.com/u/22801321/2013/october/itunes.png)

Title: Encoding with True VBR
Post by: paperskyline on 2013-10-16 18:45:52
you're looking at what QAAC has written to the tool field. the reason it says 256kbps is because that is the target bitrate. look to the left and you'll see the real bitrate for that particular file is 262kbps.

itunes does confuse things further as i already explained above. looking at the "real" bitrate in the "get info" dialog always reports 256kbps for itunes store files even though their bitrates are VBR.

this screenshot shows an EP purchased from the itunes store. note how that itunes is reporting 256kbps for all of them. but when i load the same files in foobar, they are clearly VBR.

(https://dl.dropboxusercontent.com/u/22801321/2013/october/itunes.png)

this was a convincing answer, so now the original question is that this picture shows the files are 256kbps when seen in iTunes but why aren't my files showing as 256kbps and instead it shows as "253, 231, 286... etc" in iTunes?
What is done here to make those VBR purchased files show as 256kbps in iTunes? now does everyone get the question?
Title: Encoding with True VBR
Post by: testyou on 2013-10-16 19:08:47
You could have read what you quoted.

the reason it says 256kbps is because that is the target bitrate.

Title: Encoding with True VBR
Post by: marc2003 on 2013-10-16 19:22:53
^nope, it's a different question. that quote was about QAAC and what it displays in the tool field. this is the question now:

What is done here to make those VBR purchased files show as 256kbps in iTunes? now does everyone get the question?


obviously there is metadata inside purchased files so itunes knows this and for whatever reason chooses to display 256kbps instead of the actual bitrate. as for why? you'd have to ask apple that. i'm just guessing now but one reason could be to stop people thinking they have low quality files if they have music that isn't complex and have much lower bitrates??
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-16 19:49:33
i know it is a very hard question. as this is a forum for AAC discussions, thought i'd post my queries here.
anyways thanks to those for involving in this topic. the little help so far was appreciated
Title: Encoding with True VBR
Post by: testyou on 2013-10-16 22:32:37
the little help so far was appreciated

No need to get testy.  I found your sentences hard to understand.

I think I see what you mean now.
Well I remember reading on these forums (I have no proof however) that iTunes might include different(?) codec information than what some other tools do.
If so, then when iTunes encodes a file in CVBR mode with target bitrate of 256kbps, that file is subsequently shown in iTunes as 256kbps like you see above.
And when an alternative tool is accessing the same files to encode like with qaac, it does not include that same information in the header.
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-17 06:06:02
the little help so far was appreciated

No need to get testy.  I found your sentences hard to understand.

I think I see what you mean now.
Well I remember reading on these forums (I have no proof however) that iTunes might include different(?) codec information than what some other tools do.
If so, then when iTunes encodes a file in CVBR mode with target bitrate of 256kbps, that file is subsequently shown in iTunes as 256kbps like you see above.
And when an alternative tool is accessing the same files to encode like with qaac, it does not include that same information in the header.


i guess that is the only thinkable answer at the moment
Title: Encoding with True VBR
Post by: nu774 on 2013-10-17 10:41:59
It's not written as a tag field. Unlike tag, this is pretty much standard of ISO MPEG4 and is written in DecoderConfigDescriptor, avgBitrate field in moov.trak.mdia.minf.stbl.stsd.mp4a.esds box.
It's just that iTunes (for some reason) writes constant value even when it's encoding with VBR mode.
In case of qaac, actual bitrate is written.
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-17 15:02:55
It's not written as a tag field. Unlike tag, this is pretty much standard of ISO MPEG4 and is written in DecoderConfigDescriptor, avgBitrate field in moov.trak.mdia.minf.stbl.stsd.mp4a.esds box.
It's just that iTunes (for some reason) writes constant value even when it's encoding with VBR mode.
In case of qaac, actual bitrate is written.


i get that. but itunes store doesn't encode their music using itunes, they use an external encoder. itunes encodes all the files in vbr too, but it appears as 256kbps in itunes, so why dosent it show as 256kbps when i encode a track?
what is the different procedure used to make it look as 256kbps?
*Note*: https://dl.dropboxusercontent.com/u/2280132...tember/qaac.png (https://dl.dropboxusercontent.com/u/22801321/2013/september/qaac.png)
Title: Encoding with True VBR
Post by: marc2003 on 2013-10-17 15:37:25
if you want your files to show as 256kbps inside itunes, use itunes to encode them. problem solved. 
Title: Encoding with True VBR
Post by: Nessuno on 2013-10-17 15:46:22
And, in the first place, what's the point in looking for a particular bitrate when using VBR and the QT encoder itself in this case asks for a quality parameter, not a target bitrate?
Title: Encoding with True VBR
Post by: nu774 on 2013-10-17 15:50:18
i get that. but itunes store doesn't encode their music using itunes, they use an external encoder. itunes encodes all the files in vbr too, but it appears as 256kbps in itunes

AFAIK they are using afconvert. If it's shown as 256kbps (like iTunes), then probably it means that afconvert do the same as iTunes, but I cannot say for sure since I have no access to afconvert.
You can see the value by the following command line:
Code: [Select]
mp4box -std -diso foo.m4a | findstr DecoderConfigDescriptor

In case of Unix like OS, use grep instead of findstr.

Quote
so why dosent it show as 256kbps when i encode a track?

Do you mean "encode a track by qaac"?
I already wrote the reason. iTunes (and probably afconvert) writes target bitrate into avgBitrate field, and qaac writes actual average bitrate. So they look different.
However, strictly speaking both are not spec compliant. That field shall be zero in case of VBR, acording to ISO 14496-1.
Title: Encoding with True VBR
Post by: paperskyline on 2013-10-17 18:01:33
i get that. but itunes store doesn't encode their music using itunes, they use an external encoder. itunes encodes all the files in vbr too, but it appears as 256kbps in itunes

AFAIK they are using afconvert. If it's shown as 256kbps (like iTunes), then probably it means that afconvert do the same as iTunes, but I cannot say for sure since I have no access to afconvert.
You can see the value by the following command line:
Code: [Select]
mp4box -std -diso foo.m4a | findstr DecoderConfigDescriptor

In case of Unix like OS, use grep instead of findstr.

Quote
so why dosent it show as 256kbps when i encode a track?

Do you mean "encode a track by qaac"?
I already wrote the reason. iTunes (and probably afconvert) writes target bitrate into avgBitrate field, and qaac writes actual average bitrate. So they look different.
However, strictly speaking both are not spec compliant. That field shall be zero in case of VBR, acording to ISO 14496-1.

this was enlightening. this is the info that i exactly wanted. thanks
Title: Encoding with True VBR
Post by: LocutusEstBorg on 2015-06-27 20:10:43
Recently I have been encoding music with True VBR using foobar & dbpoweramp. everything has been fine so bar, but the bitrate in itunes does not appear as "256kbps".
It appears as " 283, 271, 299, 301,,...etc."
So my question is how does the iTunes Store encode their music in True VBR, but appears as "256kbps" when displayed in iTunes?

My Settings:
dbpoweramp: -V 118 -q2 -r keep -n -R -S -o [outfile] -
foobar: --tvbr 118 --highest - %d

I even tried using "110, 113, 115"

Please try to be as much precise as possible and do not digress from the topic

I have the same problem. The correct settings for the iTunes Plus preset are "-v 256 -q 2 --no-smart-padding" (CVBR 256 kbps High Quality). The file size is very close to iTunes encoded files, but only the iTunes encoded files show "256 kbps (VBR)". My files just show "268 kbps" etc.
Title: Encoding with True VBR
Post by: Zarggg on 2015-06-27 20:55:31
In the past (and I believe still is the case) the "256 (VBR)" that you see on the iTunes encode was a nominal bitrate rather than the actual bitrate. As you see from your own encodes, the actual average bitrate may be slightly higher or lower.
Title: Encoding with True VBR
Post by: LocutusEstBorg on 2015-06-27 22:50:06
But why doesn't it at least show "(VBR)"?
Title: Encoding with True VBR
Post by: nu774 on 2015-06-28 01:26:21
But why doesn't it at least show "(VBR)"?

That (VBR) is picked from a special binary tag named "Encoding params", that stores encoding mode of iTunes (ABR, VBR) or something. Technically, there's not way to tell VBR AAC from ABR AAC just looking at an AAC file. It is just a matter of encoding strategy, and there remains no sign on the encoded result. Therefore they use that tag. Of course this "solution" should work only inside of iTunes world, and I'm not interested in it.
Title: Encoding with True VBR
Post by: LocutusEstBorg on 2015-06-28 08:38:34
But why doesn't it at least show "(VBR)"?

That (VBR) is picked from a special binary tag named "Encoding params", that stores encoding mode of iTunes (ABR, VBR) or something. Technically, there's not way to tell VBR AAC from ABR AAC just looking at an AAC file. It is just a matter of encoding strategy, and there remains no sign on the encoded result. Therefore they use that tag. Of course this "solution" should work only inside of iTunes world, and I'm not interested in it.

Can you please add an "-itunes-fields" flag or something so that it writes the encoding params and target bitrate? Most of my library is in this "256 kbps (VBR)" format and it looks inconsistent. I prefer to use qAAC since I can do multi-core conversions in parallel unlike iTunes.

Is there at least some tool which will let me modify these values without too much work?
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 09:29:54
But why doesn't it at least show "(VBR)"?

That (VBR) is picked from a special binary tag named "Encoding params", that stores encoding mode of iTunes (ABR, VBR) or something. Technically, there's not way to tell VBR AAC from ABR AAC just looking at an AAC file. It is just a matter of encoding strategy, and there remains no sign on the encoded result. Therefore they use that tag. Of course this "solution" should work only inside of iTunes world, and I'm not interested in it.

Can you please add an "-itunes-fields" flag or something so that it writes the encoding params and target bitrate? Most of my library is in this "256 kbps (VBR)" format and it looks inconsistent. I prefer to use qAAC since I can do multi-core conversions in parallel unlike iTunes.

Is there at least some tool which will let me modify these values without too much work?


Ive been asking for a encoder which can do this for a long time, qaac is very good but some people dont want all the bells and whistles that come with it. Im sure someone on this forum could easily create an encoder which encodes to itunes 256 vbr so the files come out exactly as encoded through itunes but without the trouble of using itunes. there was itunesencode buts its very old and would only encode to single core.
Title: Encoding with True VBR
Post by: nu774 on 2015-06-28 14:50:32
Can you please add an "-itunes-fields" flag or something so that it writes the encoding params and target bitrate? Most of my library is in this "256 kbps (VBR)" format and it looks inconsistent. I prefer to use qAAC since I can do multi-core conversions in parallel unlike iTunes.

Version 2.51 (now released) always writes iTunes compliant "Encoding Params" tag.
Quote
Is there at least some tool which will let me modify these values without too much work?

Since this tag is in binary form, it wouldn't be as simple as writing ordinary text tags.
Title: Encoding with True VBR
Post by: nu774 on 2015-06-28 15:03:29
Im sure someone on this forum could easily create an encoder which encodes to itunes 256 vbr so the files come out exactly as encoded through itunes but without the trouble of using itunes.

What is "exactly"? Exactly the same output including the container?
For example, iTunes writes "iTunes 12.1.2.27" into the tool tag. iTunes doesn't support TVBR, doesn't support more than 3 channels, or ADTS output. Supported tags are limited.
So, this encoder basically cannot support functionalities that iTunes doesn't support. And it always requires iTunes installation so that it can get versions and pretend to be iTunes.
I really don't understand your needs. Why on the earth such things are so important when qaac can produce bit-identical AAC bitstream?
Title: Encoding with True VBR
Post by: nu774 on 2015-06-28 15:20:33
Oh, and I forgot to mention about HE-AAC bug of iTunes. There's nearly 50-50 chance that you get truncated result out of iTunes HE-AAC encoding, and you will not able to achieve gapless playback.
If you like this, you can always use --no-smart-padding on qaac.
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 15:24:39
Im sure someone on this forum could easily create an encoder which encodes to itunes 256 vbr so the files come out exactly as encoded through itunes but without the trouble of using itunes.

What is "exactly"? Exactly the same output including the container?
For example, iTunes writes "iTunes 12.1.2.27" into the tool tag. iTunes doesn't support TVBR, doesn't support more than 3 channels, or ADTS output. Supported tags are limited.
So, this encoder basically cannot support functionalities that iTunes doesn't support. And it always requires iTunes installation so that it can get versions and pretend to be iTunes.
I really don't understand your needs. Why on the earth such things are so important when qaac can produce bit-identical AAC bitstream?

Yes so the file outputted would be identical to one encoded with itunes, I cant imagine a lot of people using the extra features included in qaac like 3 channels? or adts? Would it not be possible without an itunes installation? Basically an updated version of iTunesEncode to work with multi core.

http://www.hydrogenaud.io/forums/index.php?showtopic=35242 (http://www.hydrogenaud.io/forums/index.php?showtopic=35242)
Title: Encoding with True VBR
Post by: lvqcl on 2015-06-28 15:35:59
iTunesEncode doesn't really do encoding on its own: it asks iTunes to convert files.
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 16:06:31
iTunesEncode doesn't really do encoding on its own: it asks iTunes to convert files.

ok. If itunes wasnt so clunky to use and it accepted various formats then i would use it.
Title: Encoding with True VBR
Post by: nu774 on 2015-06-28 16:07:24
I cant imagine a lot of people using the extra features included in qaac like 3 channels? or adts?

Huh? I think TVBR is used by lots of people if I'm not wrong.
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 16:15:12
I cant imagine a lot of people using the extra features included in qaac like 3 channels? or adts?

Huh? I think TVBR is used by lots of people if I'm not wrong.


yes tvbr is useful, personally im not bothered about what encoding method is used as long as the quality is good.
Title: Encoding with True VBR
Post by: marc2003 on 2015-06-28 16:25:46
Why on the earth such things are so important when qaac can produce bit-identical AAC bitstream?


indeed. 
Title: Encoding with True VBR
Post by: IgorC on 2015-06-28 16:37:03
I cant imagine a lot of people using the extra features included in qaac like 3 channels? or adts?

Huh? I think TVBR is used by lots of people if I'm not wrong.

In my opinion one of the biggest advantage of qaac is a possibility of making a portable without iTunes being installed.  And of course, TVBR and high quality mode (q2) which are missing in iTunes .  qaac is very easy to use and even easier with foobar2000. I can't say the same for iTunesEncode and iTunes (both a.k.a butt pain).

Thank You for development of qaac and make it easier for users.
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 16:48:19
I cant imagine a lot of people using the extra features included in qaac like 3 channels? or adts?

Huh? I think TVBR is used by lots of people if I'm not wrong.

In my opinion one of the biggest advantage of qaac is a possibility of making a portable without iTunes being installed.  And of course, TVBR and high quality mode (q2) which are missing in iTunes .  qaac is very easy to use and even easier with foobar2000. I can't say the same for iTunesEncode and iTunes (both a.k.a butt pain).

Thank You for development of qaac and make it easier for users.

Yes i agree qaac is very good. Look how popular apple is in this world so a majority of people would have itunes installed, and as you cant encode to tvbr using itunes nobody knows how long it will be supported by apple. As much as i like qaac and i appreciate the effort to keep it updated etc i wouldnt imagine it would be very hard for someone to make an extra tool or upgrade iTunesEncode for the people who would use it.
Title: Encoding with True VBR
Post by: IgorC on 2015-06-28 17:06:38
Look how popular apple is in this world ...

Have a nice day
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 17:12:36
Look how popular apple is in this world ...

Have a nice day

Whats the point in saying that? is there any need? I was making a point that a majority of people would have itunes installed, just because you dont thats your opinion and thats fine!
Title: Encoding with True VBR
Post by: Zarggg on 2015-06-28 17:56:50
His point was that your assertion that "a majority of people would have itunes installed" is not only false, but useless for the purposes of this discussion.

iTunes is not the only media player. iTunes is not even the most popular media player, at least among users of this forum.
Title: Encoding with True VBR
Post by: LocutusEstBorg on 2015-06-28 18:07:37
Can you please add an "-itunes-fields" flag or something so that it writes the encoding params and target bitrate? Most of my library is in this "256 kbps (VBR)" format and it looks inconsistent. I prefer to use qAAC since I can do multi-core conversions in parallel unlike iTunes.

Version 2.51 (now released) always writes iTunes compliant "Encoding Params" tag.
Quote
Is there at least some tool which will let me modify these values without too much work?

Since this tag is in binary form, it wouldn't be as simple as writing ordinary text tags.

I don't see any difference with 2.51 in iTunes. It neither shows the constrained bit rate as 256 kbps or "(VBR)".
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 18:08:37
His point was that your assertion that "a majority of people would have itunes installed" is not only false, but useless for the purposes of this discussion.

iTunes is not the only media player. iTunes is not even the most popular media player, at least among users of this forum.

Yes its true its not the only media,but there is gonna be a hell of a lot of people who have it installed due to the amount of people who own iphones,ipads,ipods.
He made out just because qaac can be used without itunes installed then there is no need, my point is there is also a lot of people who would have it installed.
At the end of the day there is no need to get funny about it and everyone on here is allowed to have there opinion. If someone prefers to do something a certain way then thats fine there is no need to make out that person is wrong by doing it that way?
Title: Encoding with True VBR
Post by: saratoga on 2015-06-28 20:30:34
As much as i like qaac and i appreciate the effort to keep it updated etc i wouldnt imagine it would be very hard for someone to make an extra tool or upgrade iTunesEncode for the people who would use it.


Since evidently no one else is interested, why don't you be that person and do it yourself?
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 20:49:02
As much as i like qaac and i appreciate the effort to keep it updated etc i wouldnt imagine it would be very hard for someone to make an extra tool or upgrade iTunesEncode for the people who would use it.


Since evidently no one else is interested, why don't you be that person and do it yourself?

Thats fine, and if i was able to make the tool then i would.
Like ive said before whats the point in people posting negative comments??
Title: Encoding with True VBR
Post by: saratoga on 2015-06-28 21:56:24
As much as i like qaac and i appreciate the effort to keep it updated etc i wouldnt imagine it would be very hard for someone to make an extra tool or upgrade iTunesEncode for the people who would use it.


Since evidently no one else is interested, why don't you be that person and do it yourself?

Thats fine, and if i was able to make the tool then i would.
Like ive said before whats the point in people posting negative comments??


Thats a not a negative comment, its a serious suggestion.  You want something enough to argue with people who are not interested. Instead of wasting your time, why not solve the problem?
Title: Encoding with True VBR
Post by: sluggy on 2015-06-28 22:03:37
As much as i like qaac and i appreciate the effort to keep it updated etc i wouldnt imagine it would be very hard for someone to make an extra tool or upgrade iTunesEncode for the people who would use it.


Since evidently no one else is interested, why don't you be that person and do it yourself?

Thats fine, and if i was able to make the tool then i would.
Like ive said before whats the point in people posting negative comments??


Thats a not a negative comment, its a serious suggestion.  You want something enough to argue with people who are not interested. Instead of wasting your time, why not solve the problem?

I would love to be able to make it myself but wouldnt know where to start. And ive not argued with anyone ive just voiced my opinion and it seemed people had alot to say about it.
Title: Encoding with True VBR
Post by: saratoga on 2015-06-28 22:09:59
And ive not argued with anyone ive just voiced my opinion and it seemed people had alot to say about it.


You have literally spent this entire page arguing that some obscure feature should be added because you want to use it.
Title: Encoding with True VBR
Post by: nu774 on 2015-06-29 01:18:34
I don't see any difference with 2.51 in iTunes. It neither shows the constrained bit rate as 256 kbps or "(VBR)".

Works here. Confirm the following:
1) You are actually using 2.51.
2) "Encoding Params" tag is present (not removed by other tools). You can search it using hex editor and it would look like this:
Code: [Select]
00001960: 3936 0000 006f 2d2d 2d2d 0000 001c 6d65  96...o----....me
00001970: 616e 0000 0000 636f 6d2e 6170 706c 652e  an....com.apple.
00001980: 6954 756e 6573 0000 001b 6e61 6d65 0000  iTunes....name..
00001990: 0000 456e 636f 6469 6e67 2050 6172 616d  ..Encoding Param
000019a0: 7300 0000 3064 6174 6100 0000 0000 0000  s...0data.......
000019b0: 0076 6572 7300 0000 0161 6362 6600 0000  .vers....acbf...
000019c0: 0362 7261 7400 02ee 0063 6463 7600 0107  .brat....cdcv...
000019d0: 0100 0000 bc2d 2d2d 2d00 0000 1c6d 6561  .....----....mea

Title: Encoding with True VBR
Post by: nu774 on 2015-06-29 07:21:15
OK, it seems that when fb2k updates/writes tags in the m4a, it destroys existing "Encoding Params" tag. Only 4 bytes "vers" at the beginning remains. Most probably fb2k treats it's value as an ordinary text string, and bytes after NUL are discarded. It's likely that this is not only fb2k...  I dunno.
Anyway, there's nothing I can do for it.
Title: Encoding with True VBR
Post by: decollated on 2015-06-29 08:03:16
OK, it seems that when fb2k updates/writes tags in the m4a, it destroys existing "Encoding Params" tag. Only 4 bytes "vers" at the beginning remains. Most probably fb2k treats it's value as an ordinary text string, and bytes after NUL are discarded. It's likely that this is not only fb2k...  I dunno.
Anyway, there's nothing I can do for it.

Indeed. I actually made a topic about this (http://www.hydrogenaud.io/forums/index.php?showtopic=104875) last year, but nobody was interested.
Title: Encoding with True VBR
Post by: LocutusEstBorg on 2015-06-29 09:02:42
OK, it seems that when fb2k updates/writes tags in the m4a, it destroys existing "Encoding Params" tag. Only 4 bytes "vers" at the beginning remains. Most probably fb2k treats it's value as an ordinary text string, and bytes after NUL are discarded. It's likely that this is not only fb2k...  I dunno.
Anyway, there's nothing I can do for it.

I had edited the tags with dBPowerAmp which caused the Encoding Params to be lost.

However, it still does not show the bit rate as "256 kbps" for "-v 256"? Are you actually writing the target bitrate as 256 kbps now or still writing the average bit rate or zero? Does that "256 kbps" in iTunes come from Encoding Params or the average bitrate field?
Title: Encoding with True VBR
Post by: nu774 on 2015-06-29 09:32:02
I had edited the tags with dBPowerAmp which caused the Encoding Params to be lost.

Ha ha, so fragile. it's undocumented, binary tag only used by iTunes and nobody cares.
If you want consisntency, why don't you scan your whole library for replaygain by fb2k? Your (VBR) markers in iTunes will be all lost.

Quote
However, it still does not show the bit rate as "256 kbps" for "-v 256"? Are you actually writing the target bitrate as 256 kbps now or still writing the average bit rate or zero? Does that "256 kbps" in iTunes come from Encoding Params or the average bitrate field?

Bitrate in "Encoding Params" is nominal value. Bitrate is written in the form of 4 bytes big-endian integer in this part, after "brat"(=62 72 61 74).
In this example, the value is 0x0002ee00 = 192000. In your case, it should be 0x0003e800.
Code: [Select]
000019c0: 0362 7261 7400 02ee 0063 6463 7600 0107  .brat....cdcv...

As far as I can see, iTunes picks this value as bitrate when "Encoding Params" is present. You can confirm it by overwriting this value using hex editor or something.
Title: Encoding with True VBR
Post by: sluggy on 2015-06-29 12:06:41
Yes i can confirm when encoding with dbpoweramp the Encoding Params tags get lost.
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