Skip to main content
Topic: Encoding with True VBR (Read 15470 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Encoding with True VBR

Reply #50
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.

Encoding with True VBR

Reply #51
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


Encoding with True VBR

Reply #52
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.

Encoding with True VBR

Reply #53
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 last year, but nobody was interested.

Encoding with True VBR

Reply #54
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?

Encoding with True VBR

Reply #55
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.

Encoding with True VBR

Reply #56
Yes i can confirm when encoding with dbpoweramp the Encoding Params tags get lost.

 
SimplePortal 1.0.0 RC1 © 2008-2018