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Topic: low bitrate on portable players (Read 10391 times) previous topic - next topic
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low bitrate on portable players

Hello,

who has got experience on the performance of portable hardware players (flash) with low bitrate (<q0) vorbis files? AFAIK some players (trekstor, cowon(?)) won't play these at all, but what about the rest?

What about the Samsung YP-U1Q & YP-U2Q or the iriver T30, for example?

The specifications only (if any) state an upper quality limit (q9 or 10), but no lower limit, but as these limits exist on other devices, they might be a common thing.

I am thinking about buying a portable player to listen to music, as well as low-bitrate encoded audiobooks, so low-bitrate compatibility would be a necessary feature.

Another question is, whether the playback of such low-bitrate-files will reduce battery life significantly.

Thanks in advance for sharing your experience!

Greets
Stuffi

low bitrate on portable players

Reply #1 –
at least with vorbis there should be no lower limit at all imho (but iam guessing here.)
PANIC: CPU 1: Cache Error (unrecoverable - dcache data) Eframe = 0x90000000208cf3b8
NOTICE - cpu 0 didn't dump TLB, may be hung

low bitrate on portable players

Reply #3 –
My Samsung YP-MT6 skips files encoded at quality < 0. But from -q0 to -q10 plays well.

low bitrate on portable players

Reply #4 –
Why is it that some players don't decode low bitrate Vorbis files well? I always thought that high bitrates require more CPU power, but low bitrates? Is the memory demand higher or what?

low bitrate on portable players

Reply #5 –
iRiver T10 plays from q1 to q10. Some (less than 10%) of q1 using libvorbis 1.1 skip. Q2 always playe well. The T10's chip supports ogg from 80 kpbs (which is the nominal bitrate for q1).

I encode at q1 and when I find a track that is not played I reencode it with q2. I get very small files. I encoded X&Y in 32 MB this way.

low bitrate on portable players

Reply #6 –
Being someone who likes to think that he has a clue about how Vorbis works: I don't know why low bitrate .oggs are not supported on some units.

<conspiracy-theory>
Maybe the ppl who built those units have a contract with Microsoft forcing them to ignore low bitrate oggs because they sound too good in comparison to WMA std?
</conspiracy-theory>


Regarding memory demand: One could check how the size of the "codec setup packet" compares among different -qX encodes. That might give a hint about memory demand.

I havn't checked whether "bigger" codebooks are used for lower bitrates to sqeeze out the last bits of redundancy. Could be possible, though unlikely I suppose. (By "bigger" I mean high dimensional codebooks which require more working memory)

low bitrate on portable players

Reply #7 –
Quote from: iGold on
My Samsung YP-MT6 skips files encoded at quality < 0. But from -q0 to -q10 plays well.


That's most likely due to "quality<0" files having larger block sizes (using currently available encoders).
Instead of 1024 (long) or 128 (short packet) samples/channel/packet they are both twice as big for quality<0 files.

low bitrate on portable players

Reply #8 –
Quote
I havn't checked whether "bigger" codebooks are used for lower bitrates to sqeeze out the last bits of redundancy. Could be possible, though unlikely I suppose. (By "bigger" I mean high dimensional codebooks which require more working memory)


Wasn't that the problem with peeling too? it would require arbitrarily large codebooks? I honestly think it's the incompetence of development teams, but that's just me ;D

Quote
That's most likely due to "quality<0" files having larger block sizes (using currently available encoders).
Instead of 1024 (long) or 128 (short packet) samples/channel/packet they are both twice as big for quality<0 files.


This is true 

Quote
Maybe the people who built those units have a contract with Microsoft forcing them to ignore low bitrate oggs because they sound too good in comparison to WMA std?


I would be more worried about competition from Apple then from Windows. I am sure they have had a few scouts who have dropped by these forums, in fact I am willing to bet they have even dropped in some messages here and there ;o
budding I.T professional

low bitrate on portable players

Reply #9 –
Quote from: stuffi on
Another question is, whether the playback of such low-bitrate-files will reduce battery life significantly.

It changes with models.
On PC, the bit rate and CPU load usually link.
(low bitrate = small load)

low bitrate on portable players

Reply #11 –
iRiver has a transcoder which I don't think is any better than current encoders. Even their encoder produces files which might have bitrates lower than 96 kbps depending on the complexity of the track.

low bitrate on portable players

Reply #12 –
My iFP-895 will normally ignore oggs that average below 96 kbps, but there is a firmware hack that removes that limitation. The only problem I've seen is that occasionally it'll get stuck at the end of a track and loop the last second or so over and over until you skip to the next track. I normally use -q2 and haven't had any other problems with files that averaged down in the mid-80's.

low bitrate on portable players

Reply #13 –
If manufactures say that they don't support "oggs below 96 kbps" and this is really due to other/bigger codebooks in use (by current encoders) then Vorbis files should play fine using -q2 and above -- even if the bitrate drops below 96 kbps -- because the encoder selects codebooks based on the quality level.

Has anyone tried "easy-to-encode" tracks encoded at -q2 with a lower bitrate than 96 kbps on those players? Do they play?

Edit: I just read the above post which answers my last question. I guess I'll do some setup packet size measuring ...

Edit2: I checked the offsets for the 3rd Ogg page (containing the first audio packet) for different quality encodes (rather old oggenc with libVorbis 1.0.1):
Code: [Select]
q0 :  F45h
q1 :  E2Dh
q2 :  F66h
q3 :  F8Bh
q4 : 1083h
q5 : 1083h

Looks like the size of the codec setup packet doesn't fluctuate that much at different q-values.

low bitrate on portable players

Reply #14 –
Personal experience :
iRiver iFP-series don't do well on Ogg.  ABR at 128 seems to work every time.
iRiver T30 - everything from Q-1 to Q7 works flawlessly.  Haven't tried Q8 or higher.
Samsung YP-MT6 - everything from Q-1 to Q7 works but volume seems slightly lower than the equivalent MP3.  Firmware 2.29.
Samsung YP-Z5 - q-1 to q7 works great.  Battery life suffers by maybe 15%.
 

low bitrate on portable players

Reply #17 –
Did a little more testing with my iFP-895 and found that q-1 won't work, the player reports "NOT A SUPPORTED OGG FORMAT" or some such message while q0 and greater worked fine. I've switched to using q1 from q2, still sounds good enough for portable use, tried q0 but didn't like the way it sounded.

low bitrate on portable players

Reply #18 –
Thanks you for your input!

I now bought a Samsung YP-U1 Q, the manufacturer says that it plays ogg-vorbis from q0 to q10 and this seems to be true (I haven't tested q10, though).

Q0 worked fine, even if the actual average bitrate was fairly below 64kb/s (52,6kb/s). Q-1 didn't work.

Stuffi

low bitrate on portable players

Reply #19 –
For the iRiver and the Apple iPod, alternative RockBox firmware seems to be able to decode vorbis files with low bitrates.

low bitrate on portable players

Reply #20 –
This really does seem like a thorn in ogg's side, with regard to player support. What's the point of having a standard if 1/2 the manufacturers are only going to support part of it. Is it really that hard to implement a full range of bitrate support?

low bitrate on portable players

Reply #21 –
Quote from: loophole on
This really does seem like a thorn in ogg's side, with regard to player support. What's the point of having a standard if 1/2 the manufacturers are only going to support part of it.


Yes. If it weren't for the missing low bitrate support I would have bought the trekstor ibeat organix. 

For me q0 support is sufficient, as --resample and --downmix allow making quite small files (with acceptable quality for audiobooks) at q0, which will play at my YP-U1Q.

But one of the main reasons for using vorbis (apart from OSS issues) is the good quality at low bitrates - I doubt that a lot of people are able to distinguish between ogg and mp3 at 192kbit/s, but at 64kbit/s it's relatively easy.

low bitrate on portable players

Reply #22 –
Does any of theese players support vorbisgain/replaygain!? (and while we are at it, gapless playback?)

Im thinking of buying the iriver t30 cause of the ogg support but im so in love with replaygain i can't stay away from it. Is it possible to add gain to the file itself as with mp3gain!?

low bitrate on portable players

Reply #23 –
To be on the secure side, simply buy a device supported by the Rockbox firmware. It works with both Replay Gain and gapless playback for Vorbis files. Sadly, the iriver t30 you wanna buy isn't listed there.

Edit: And no, Vorbis files aren't directly manipulated when applying their gain. They receive the appropriate tags instead. The only exception is john33's OggDropXPd encoder which allows scaling the files' loudness based on FLAC Replay Gain tags. Note that this process is irreversible and also not too exact for the resulting Vorbis files - lossless and lossy files' loudness and therefore also their Replay Gain informations slightly differ from each other.

In case you were interested in playing around with this encoder, it can be found on http://rarewares.org/ogg.html.

Edit 2 (looks like I'm already a bit sleepy): One more thing: If you choose to scale the volume using FLAC Replay Gain tags don't forget to check "Do not copy FLAC Replay Gain tags from input file" in the "Encoding Options" window. Otherwise, the already scaled files' loudness will be Replay Gain processed by a player which is compatible to it, resulting in an additional change in playback volume.

Edit 3 (goddamn, sleepy head... *sigh*): I somehow forgot the "Replay Gain Processing" offered in the Converter of foobar2000. Used during encoding it irreversibly alters the audio data, unlike being used after the conversion process has finished. This should result in what you asked for as well, although I'm not quite sure since I never use Replay Gain during encoding myself. At the moment I'm also too tired/lazy to test it.

low bitrate on portable players

Reply #24 –
Thx for the info, im actually gonna buy an ipod nano later on but i need a smaller one for the moment.

Gonn check the foobar thingy

BTW, does _EVERY_ ipod nano that exists work with Rockbox? (I read somewhere that there are dif versions avail)


EDIT: man that foobar setting use replaygain rocked!! solid solid.. now im gonna buy the t30 $$$