Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: LAME 3.98 ABR bug ? (Read 5225 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

LAME 3.98 ABR bug ?

There is a strange behaviour that is only obvious at 280+ k bitrate. Below is a comparison of v3.98 and older encoders - target bitrate (produced bitrate). Over 20 samples were tested. At 288k the psymodel uses max tunings as far as I know so a *slight* rise is normal. V3.98 bitrate looks very strange.


Lame 3.98: target 280 (291), 288 (316)
Lame 3.97: target 280 (269), 288 (282)
Lame 3.90: target 288 (289)

LAME 3.98 ABR bug ?

Reply #1 –
perhaps things are messed up due to the mix of vbr-old and vbr-new not fully switched?

i could be lying, tho.


later

LAME 3.98 ABR bug ?

Reply #2 –
This behaviour is because of the restricted bit reservoir usage. You can see a similar effect with 3.97 if you add --strictly-enforce-ISO

LAME 3.98 ABR bug ?

Reply #3 –
robert, that is what i initially posted, but i did some encodings and the behavoir was much different.

--strictly-enforce-iso adds more bloat to both 3.97 AND 3.98b4 and doesn't address the OP


later

LAME 3.98 ABR bug ?

Reply #4 –
You are right, the switch --strictly-enforce-ISO is a harder constrain than what we had to add to work around the FhG decoder bug. But the effect is similar.

LAME 3.98 ABR bug ?

Reply #5 –
v3.98

--preset 270 (274)
--preset 265 (266)
-V0 -Y          (218) - 225 is probably average without sbf21 issue.

v3.97

--preset 270 (262)

I guess this is more inline with the expected bitrate. I am simply testing a 'braindead' setting that gives more headroom over -V0 yet much smaller than cbr320. Bitrate should be 260~280k range. Goal is to have the advantages of cbr320. Transcoding, DSP application like vocal cut , some problem samples are still issues for -V2 / V0. In my experience -b320 is usually excellent in these cases and so far 265k abr is a good candidate . I'll post more of my findings soon.
 

LAME 3.98 ABR bug ?

Reply #6 –
Quote from: shadowking on
... In my experience -b320 is usually excellent in these cases and so far 265k abr is a good candidate ....

Quite interesting cause this is pretty much what I did when I had my archive encoded with 3.90.3. I used ABR 270 then and didn't encounter a disadvantage against CBR 320.
lame3995o -Q1.7 --lowpass 17