What are the best behaved audio file formats for RockBox?

[gonzalexx]

I did ask this question in another post... as part of it... it was a reply... but probably won't get seen that much... so now... officially... I'm asking:

What are the best behaved audio file formats for RockBox?

Thanks for all the work... and for not asking if I have read the manual... I have... but it would be nice to have a live answer from both devs and users.

Thanks for your time and effort!

[cool_walking_]

I mostly use Ogg Vorbis, with a few MP3s for podcasts and such, and I don't think I've ever had problems specific to either one.  I've experienced playback bugs, but they didn't have anything to do with the file format.

I never took much notice, but the formats need differing amounts of processing (and thus battery) to decode:
http://www.rockbox.org/wiki/BatteryRuntime

Also this:
http://www.rockbox.org/wiki/CodecPerformanceComparison
My understanding is that higher percentages are better because the faster the decoding is done, the sooner the CPU can be clocked back down to low speed.

[gonzalexx]

Thank you cool....

Excellent insight!... so in codecs... it appears that FLAC wins.

and here comes a newby question... what do you guys mean by "realtime"... as opposed to what?

Thanks so much for your response... so many formats, so little time.
Take good care... and enjoy.

[cool_walking_]

"Realtime" as in the actual time of the song. So if a 3 minute long song decodes in 3 minutes, that's 100%.  You actually want to be decoding at more than 100% (I've read 120% or 130%), so that you don't get any skips in playback.

Keep in mind that FLAC is a lossless codec, so it takes up much more HDD space than lossy formats like Ogg Vorbis, MP3, WMA, etc.

[Llorean]

For playback, two things really cost battery. CPU and disk spinning. So lossless like FLAC may be faster but because they are bigger, you spend battery spinning the disk more. You want to find a happy point with small files that still decode pretty fast.

[gonzalexx]

Excellent!!!
Thank you guys...
There's some playing to be done then.  I haven't used decoders deliberately before... of course, by deliberately I mean aware of the difference they make in playback, since that's the magic of your standard players... they make everything seem transparent and seamless to the listener... a file will sounds pretty much the same... but when I noticed the different behavior from rockbox with my old ipod... I started to wonder.
In fact, before rockbox was in my box, the old battery would last very little, but it was predictable... then I went on vacation to Alaska, and in the cold.... well... it would not last at all... then... back home in the tropics, it was back to its predictable behavior until I loaded rockbox, and started noticing very significant differences in battery usage... so I did order a nice battery replacement, so I can see the behavior as it should be seen... it was about time too.
Now I have more reasons to mind file formats, and decoders.
Thanks for the eye openning experience!!!

[Zardoz]

Hi gonzalexx
I'm no expert, neither am I a developer but I'll add my two-cents nonetheless.
I've always favoured .ogg or .mpc. I'd recommend musepack I think - it seems to introduce less 'artifacts' and decodes pretty smoothly across all Rockbox targets. It's a naturally or native variable-bit-rate codec so it optimizes the compression as well as can be expected (--quality 4 works well for me.) I guess it's one of the least well supported codecs 'out there' so if you plan to move files to commercial players using original firmwares it's, maybe, not a good choice (except for most Cowon players.)
The less compression/encoding done the less decompression/decoding needed so I guess it goes without saying that a lossless codec (.flac, .ape etc) is slightly better in terms of processor load than a lossy one. But as cool_walking and Llorean said, the file will be bigger and take longer to read/buffer.
Codec performance seems to vary (pretty dramatically) across targets. I use an ipod 5.5g 80GB, for my sins and .mpc or .mp3 works best for me in real-speak.
Sorry for the long, non-committal reply!!
keep the faith
z

[soap]

The less compression/encoding done the less decompression/decoding needed so I guess it goes without saying that a lossless codec (.flac, .ape etc) is slightly better in terms of processor load than a lossy one.

Not true in two ways:
1:
FLAC was designed to be asymmetric and decode easily.
Whereas:
APE is the MOST processor intensive of the codecs.*
2:
Lossless codecs are not "less compressed" than lossy codecs, they are differently compressed.  Think of a lossy codec not as a more powerful lossless codec, but as a lossless codec which also takes into account what the human ear can actually discern, and throws away data that:
A - It knows you can't hear.
(and when asked to lower bitrate more, data:)
B - You will be less likely to notice is missing.


*Ok ok ok, APE at the compression level most people use it at is the slowest codec. 

[Zardoz]

FLAC was designed to be asymmetric and decode easily.
Whereas:
APE is the MOST processor intensive of the codecs.

OK I stand corrected 

I understand how codecs 'discard' the least necessary information. It's how they determine the necessity or not that distinguishes them?

Like I said I'm no expert. My (limited) sense of logic said if a thing didn't need to be squished too much, then another thing didn't need to un-squish it too much, and all that un-squishing is done by the processor in the (rockbxed)player. The less un-squishing the better, n'est pas?

[AlexP]

Like I said I'm no expert. My (limited) sense of logic said if a thing didn't need to be squished too much, then another thing didn't need to un-squish it too much, and all that un-squishing is done by the processor in the (rockbxed)player. The less un-squishing the better, n'est pas?

That doesn't follow at all.

It all depends on the algorithms used to do the compressing/uncompressing.  A codec could use a horrendously inefficient algorithm that is both computationally very expensive but still doesn't compress well.

[Zardoz]

I stand corrected again 

[gonzalexx]

Thank you again guys...
I'm getting an education here.
The things one takes for granted can suck up performance/battery.
I'm still waiting for my new battery, so I can then see true-to-life performance with rockbox, until then, I won't really know what factors I can pick and choose with file formats and codecs.
For now... I'm using whichever default encoding was used with my files... I don't do a whole lot of encoding at this point in time, but being picky about what I put in the player will go a long way saving battery... so I'm checking it out more closely.
Of course, the battery issue will go away soon... and then I can focus on file specs to see the truth.
How about suggestions for the regular user that just gets audio and doesn't even look at the specs?... most of these folks Itune-it, of course, but the origin of their files makes the specs vary, and they're subject to the whims of the audio originators?... maybe the question here would be:
"What are the most used file formats and codecs out there in the collective audio pool of the internet?"
You guys really know your stuff... (and I'm not even looking at video formats and codecs !!!!).
Thanks for all the feedback.

[soap]

When in doubt, stick with MP3 encoded with LAME -V2.
If you want to learn more, hydrogenaudio is the appropriate place.

[gonzalexx]

Thank you soap!

That seems to be the consensus so far.
I am going to check what some of my files are, because it seems, and probably by the nature of the files one finds out there, that there are various popular codecs being used.
So far... I think I need other programs to find out details per file... although I probably have the tools already... I haven't purposely checked out all my options.  Downloaded the apparently famous foobar2000 to check it out... it seems that is used as a utility around here.
Wish I had time to play more with the toys, but as fathers go... family does take my time, and I can only glance for a few minutes at a time so I have to break my fact finding sessions to account for my 4 year old's slowly expanding attention span (I think one ends up forcing that same attention span unto oneself in this situation!).
Anyway... this is one of the things I do between having Dora, Backyardigans, and countless other things in my environment that would drive many adults crazy - but hey... you got to love it!
So... a little escape into tech-world is quite a treat... even if it is shortlived.

Anyway... I shall find out some more about my files... music, audiobooks, etc... in mp3, apple, and other formats... it is interesting to find out about the many formats and audio resolutions out there... (I do hate to get an audiobook in very low bitrates though... transistor radio time)

Thanks for your input, and patience with the still uninitiated!