Problem with embeded album art of mp3 and ogg

[maz-1]

many　of　my　songs　are　embeded　with　album　art(most are jpeg),but not all album arts are shown on rockbox(while it works all right in foobar2000).I did a test with photoshop.I export a picture in jpeg format with different options and insert exported pictures into a mp3 file with foobar2000,and when the embeded album art is exported with option 'optimized baseline',it cannot be displayed in rockbox.but if i extract the embeded picture that cannot be shown in rockbox to an individual file naming'cover.jpg',it can be shown in rockbox.On the other hand,all embeded album art of ogg files cannot be shown in rockbox,doesn't rockbox fully support vorbis tag?

[maz-1]

P.S.i test it on my sansa fuze v2 player and ipod classic emulator

[saratoga]

See here:

http://download.rockbox.org/daily/manual/rockbox-sansafuzev2/rockbox-buildap3.html#x19-371000C

[maz-1]

Still don't understand why embeded album arts of 'optimized baseline' differs from　other ones.Or 'unsynchronized'(as is mentioned in wiki)is a kind of expression of 'optimized baseline'?

[maz-1]

'Rockbox does not support RLE-compressed BMP files, nor does it support progressive and multi-scan JPEG files.'
this is grabbed from the link provided above,is this for both embeded album arts and individual ones?And does it has anything to do with optimized baseline jpeg files?

[saratoga]

'Rockbox does not support RLE-compressed BMP files, nor does it support progressive and multi-scan JPEG files.'
this is grabbed from the link provided above,is this for both embeded album arts and individual ones?

Yes, the same JPEG limitations apply to all files; like the manual says JPEG variants that would need more memory than is available are not supported. 

[maz-1]

Does embeded album arts in idv3 have more limits than individual album arts when stored as jpeg?(don't quite understand what　'unsynchronized'　means)

[saratoga]

Does embeded album arts in idv3 have more limits than individual album arts when stored as jpeg?(don't quite understand what　'unsynchronized'　means)

unsynchronized refers to a type of ID3V2 tag.  JPEG has no additional limits, but if you use a type of tag we can't read, the JPEG file won't be parsed. 

FWIW, unless you're a developer, there should be no reason for you to care about how JPEG or ID3v2 work.  Just use normal JPEG files with any sane tag writing software and everything will work.  You'll only run into problems if you try to force weird JPEG features that no one ever uses.  Don't do that. 

[maz-1]

well,i don't know if i explained my question clearly enough.You have just said that if individual  album arts in jpeg format work fine in rockbox then they should work fine when embeded into idv3 with proper tools,right?the problem is that optimized baseline jpeg album arts can be displayed when stored as  individual files,but when these pictures are embeded into mp3, they don't work.And the same problem doesn't happen on standard baseline jpeg files or continuous jpeg files(i did several tests ,kept other conditions the same).So the only explaination is that embeded album arts have more unexpected limits than individual album arts.I'm not sure if foobar2000 can be seen as a proper tool for tag writing.

[saratoga]

I don't know what optimized baseline jpeg is, I don't think thats an official JPEG term.  I can look at one of the MP3s that doesn't show album art though if you post a link.

Edit:  Google says the "optimized baseline" feature is just normal baseline produced by Photoshop, so I don't see why it would be any different. 

[maz-1]

This one,for example.
https://skydrive.live.com/redir?resid=EED7455B8FCA288F!157
If you extract the embeded album art to the same folder that the mp3 file locates,then the extracted jpeg file can be shown on the wps interface
And as for optimized baseline in Photoshop，I think it is the option selected in the picture below,the normal baseline should be the first option though...And I think optimized baseline is a feature supported by rockbox,because it can be shown both in image viewer and wps interface as long as the picture is stored as a individual file.So it is strange that when embeded into mp3 the picture won't show up.

[saratoga]

If I strip the tags with foobar (or change between ID3v2 tag variants so that the entire tag is rewritten from scratch), the covert art displays, so I think its just something weird with the ID3v2 tags.