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Topic: Does the bitrate constraining not work on vorbis? (Read 5656 times) previous topic - next topic
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Does the bitrate constraining not work on vorbis?

Some players (yeah, iRiver) implements Ogg Vorbis with restrictions on bitrate. I've tested using:

Code: [Select]
oggenc -q6 -m96 -M225


in order to reach the necessary restrictions, but I see several files that are not encoded as I expected. Even if I try:

Code: [Select]
oggenc -b192 -m96 -M225


It doesn't seem to work. Although the codec displays that constraining is under way, some files get bitrate below or above the limits I determined.

Sincerely I think the first option should be prefered, because of the quality gains associated with -q6 upwards, but no one works. I must admit that I've not really tested the files on a player, because I don't own one yet, it is simply a preliminary investigation. Any explanations are welcome.

Does the bitrate constraining not work on vorbis?

Reply #2 –
A quick test of using --managed versus not results in exactly the same file using the Vorbis Megamix, and I'm seeing bitrate spikes into the 400s even with -M225. I'll try again with the Xiph oggenc. EDIT: Same deal with Xiph, I'm gonna do a few more tests and get back.

Now correct me if I'm uninformed, but I was under the impression that iRiver only disliked average bitrates for entire files outside that range, and didn't mind individual frame sizes outside of that range.

Does the bitrate constraining not work on vorbis?

Reply #3 –
Vorbis megamix is based on aoTuV beta 2, which means that it is not advisable to use the bitrate management mode.  1.1 rc1 fixed this issue.

Does the bitrate constraining not work on vorbis?

Reply #4 –
Quote
A quick test of using --managed versus not results in exactly the same file using the Vorbis Megamix, and I'm seeing bitrate spikes into the 400s even with -M225. I'll try again with the Xiph oggenc.[a href="index.php?act=findpost&pid=225110"][{POST_SNAPBACK}][/a]

There used to be a bug in the library that could stop bitrate managing from working nicely with unofficial tunings. Megamix doesn't have a fix for that bug, yet.

Does the bitrate constraining not work on vorbis?

Reply #5 –
Quote
Now correct me if I'm uninformed, but I was under the impression that iRiver only disliked average bitrates for entire files outside that range, and didn't mind individual frame sizes outside of that range.


What I find quite funny is that no real iRiver user has, as far as I know, elucidated this point. I have also thought like you, although to me it seems more logical that restriction applies to frame than to average bitrate. I simply don't know what to think. I know that their forum are full of people quite dissatisfied.  But obviously for other reasons too, so I'll not insist on it.

Any way it is a pain to use a audio format with such "cares". And it would be nice to know exactly which ones before any purchase.

Does the bitrate constraining not work on vorbis?

Reply #6 –
I did a quick test, and Foobar reports no difference between the audio streams of the managed (-q6 -m96 -M225 --managed) and unmanaged (-q6) versions of both the latest Xiph and Megamix.

Does the bitrate constraining not work on vorbis?

Reply #8 –
Quote
What I find quite funny is that no real iRiver user has, as far as I know, elucidated this point. I have also thought like you, although to me it seems more logical that restriction applies to frame than to average bitrate. I simply don't know what to think. I know that their forum are full of people quite dissatisfied.   But obviously for other reasons too, so I'll not insist on it.

Any way it is a pain to use a audio format with such "cares". And it would be nice to know exactly which ones before any purchase.
[a href="index.php?act=findpost&pid=225123"][{POST_SNAPBACK}][/a]


I am a real iRiver user. I own a SlimX 550, and it has been flashed to the beta firmware that supports Vorbis, though admittedly before reading this thread I hadn't bothered to try it. *After* reading this thread, I grabbed the auTuVb2P3 build of oggdropXPd, and ripped and encoded three tracks at q=4 just to make sure the ogg support works.

I know that it is possible the bitrate goes below the 96kbps floor that the iRiver site suggests. But so far, all three played and I haven't heard any of the tracks skip. I *have* noticed that the player sure doesn't like to go backward in a list of Ogg Vorbis tracks for some reason, though . What tools do you use to get bitrate info for a file?

Now, the reason I'm posting other than to make that somewhat useless confirmation, is that I'm willing to volunteer perform any tests that you guys would like. Just give me the methodologies ... I'm willing to encode any tracks that I have, or play any .ogg files that you've made that you want me to try.

Does the bitrate constraining not work on vorbis?

Reply #9 –
Quote
Quote
What I find quite funny is that no real iRiver user has, as far as I know, elucidated this point. I have also thought like you, although to me it seems more logical that restriction applies to frame than to average bitrate. I simply don't know what to think. I know that their forum are full of people quite dissatisfied.   But obviously for other reasons too, so I'll not insist on it.

Any way it is a pain to use a audio format with such "cares". And it would be nice to know exactly which ones before any purchase.
[a href="index.php?act=findpost&pid=225123"][{POST_SNAPBACK}][/a]


I am a real iRiver user. I own a SlimX 550, and it has been flashed to the beta firmware that supports Vorbis, though admittedly before reading this thread I hadn't bothered to try it. *After* reading this thread, I grabbed the auTuVb2P3 build of oggdropXPd, and ripped and encoded three tracks at q=4 just to make sure the ogg support works.
[a href="index.php?act=findpost&pid=227949"][{POST_SNAPBACK}][/a]


I own an iRiver iMP-400, and after reading this thread 'upgraded' the firmware to the latest version. I encoded a few songs using aoTuV b2 on q4.99 and tried them out. I have only noticed skipping in two songs (though haven't tried them all yet). One song had an average bitrate of only 141, and the other was below the 255 threshold. Is there any tool to analyze ogg's and see the distribution of bitrates within the file?

Does the bitrate constraining not work on vorbis?

Reply #10 –
Quote
Now, the reason I'm posting other than to make that somewhat useless confirmation, is that I'm willing to volunteer perform any tests that you guys would like. Just give me the methodologies ... I'm willing to encode any tracks that I have, or play any .ogg files that you've made that you want me to try.
[a href="index.php?act=findpost&pid=227949"][{POST_SNAPBACK}][/a]


QuantumKnot, or some other vorbis' guy, could provide these samples, in order to elucidate the point.  Although I presume these guys prefer the Karma, for its full support. 

Does the bitrate constraining not work on vorbis?

Reply #11 –
Quote
Quote
Now correct me if I'm uninformed, but I was under the impression that iRiver only disliked average bitrates for entire files outside that range, and didn't mind individual frame sizes outside of that range.


What I find quite funny is that no real iRiver user has, as far as I know, elucidated this point. I have also thought like you, although to me it seems more logical that restriction applies to frame than to average bitrate. I simply don't know what to think. I know that their forum are full of people quite dissatisfied.  But obviously for other reasons too, so I'll not insist on it.

Any way it is a pain to use a audio format with such "cares". And it would be nice to know exactly which ones before any purchase.
[a href="index.php?act=findpost&pid=225123"][{POST_SNAPBACK}][/a]


Hi, I own an IFP 590 and my experiences are like this:
- I had no problems so far concerning the lower limit of the bitrate.
- The device refuses to play songs with an average bitrate above 320 kBit/s.
- If certain parts of a song exceed the ~ 320 limit I get dropouts ( I noticed it with some applause at the beginning of a song) (latest Manager firmware version).

Hope this helps

Johnb

Does the bitrate constraining not work on vorbis?

Reply #12 –
It does me...thanks. A few of my -q 8's are over 320 (high is 349 kbs) which were Xiph Vorbis 1.00 encodes. Have since dropped down to -q 7 with stock Xiph 1.01 encoder. Interested in the iHP-140 and assume the ogg decoder is at least as burly as what's in your iFP.

xen-uno
No one can be told what Ogg Vorbis is...you have to hear it for yourself
- Morpheus

Does the bitrate constraining not work on vorbis?

Reply #13 –
I've got dozens of albums encoded in q6 on my H120 and never noticed a single problem with it. It's best to ignore the official iriver forum btw...

Does the bitrate constraining not work on vorbis?

Reply #14 –
iRiver iHPs officially support vorbis format at 64-500 kbps. Bitrate restrictions affect flash-memory players (iFP) and CD players (iMP). It has been verified by several users.
Wavpack Hybrid: one encoder for all scenarios
WavPack -c4.5hx6 (44100Hz & 48000Hz) ≈ 390 kbps + correction file
WavPack -c4hx6 (96000Hz) ≈ 768 kbps + correction file
WavPack -h (SACD & DSD) ≈ 2400 kbps at 2.8224 MHz
 

Does the bitrate constraining not work on vorbis?

Reply #15 –
Hi, I've also an iRiver iMP 550. (with the 1.70 firmware)
I encode some albums with Megamix2 -q 4. But there are some files below the supported 96kbps. (particularly oldies)
Others have > 200kbps average. The songs with the high bitrate sometimes stutters. I think this happens to frames with a bitrate above the supported 256kbps.
I've also tried to encode with the "-q 4 -m 96 -M 225" switches.
Unfortunately without success.

Quote
Is there any tool to analyze ogg's and see the distribution of bitrates within the file?
That's exactly what I search for.