Opus - playback skips beginning of files that have embedded artwork.

[bilditup1]

This was previously reported upon a couple of years ago, and I'm sorry to say that I seem to be having the same issue on my Clip Zip and XDuoo X3 (yes, I understand you guys aren't directly responsible for that build) using 3.14, where playback skips around the first few seconds. The lower the bitrate, the more severe the issue is - so on a ~180kbps file, the first second or so will play, before skipping over to 00:04, but on a ~64kbps file, 00:01-00:02 will play, before skipping over to 00:06. (Actually, on the Clip Zip, play back of the first or second second doesn't even happen - it just skips straight to 00:04 or 00:06.)
The files appear to have been encoded using the latest stable build, libopus 0.1.10, specifically the build that ships with foobar2000's encoder pack (both 2017-06-27 and the latest 2017-10-27 update), but not all of the files so encoded suffer from this issue. I have not been able to isolate the differences as yet, or to the encoding session, or anything. (I do have, by mistake, two sets of opus files of the same albums that I encoded about a week apart, with the same encoder setup and settings, the later one of which doesn't suffer from this issue, but I couldn't tell you why). I'm also not sure if files encoded with earlier Opus builds are similarly affected. Probably I should make a bug report about this, but I don't really remember how to do so properly, so I decided to post here first.)

ED: So natch right after posting I realized what I'd missed: the files that wouldn't play back properly had album artwork - not even large album artwork, we're talking just 50-60kb - embedded into them, which were added either during the original encode, or later on using mp3tag (even using the latest version, 2.85). Removing the album art solves the issue on both my Clip Zip and XDuoo X3. I'm not yet sure if this is universally the case, or only true for file created or manipulated with libopus 0.1.10, but I feel more confident filing a report now.

[bilditup1]

I have filed a bug report here:
https://www.rockbox.org/tracker/task/13133

In the meantime, it seems like the largest artwork that can be safely attached without causing these skips at the beginning of tracks must be 45.6KiB. (I haven't actually confirmed that, but 45.8KiB definitely doesn't work. 45.7KiB might, but it's hard to generated jpgs of arbitrary size.)

[ats1995]

I can confirm similar symptoms on my Clip Zip running 3.14 when playing back opus files with embedded album art larger than ~46KiB. It plays the first fraction of a second before skipping ahead around 3 seconds. I've encoded at 128kbps VBR with foobar2000 1.3.17 with Free Encoder Pack 2017-10-15.

I also experience frequent crashes and hangups to the point where it's unusable to me. I snapped photos of the crash screens for a while, but stopped bothering after a while. See attachment. I've reinstalled Rockbox two times. The crashes persist.

After finding your bug report I removed all attached artwork and am currently working on re-encoding my library.

[saratoga]

I also experience frequent crashes and hangups to the point where it's unusable to me. I snapped photos of the crash screens for a while, but stopped bothering after a while. See attachment. I've reinstalled Rockbox two times. The crashes persist.

This is probably an unrelated issue due to voltage scaling.  Can you try this older build:

http://web.mit.edu/mgg6/www/rockbox-clipzip-3f54101.7z

[ats1995]

After re-encoding my library without embedded album art, my Clip Zip on 3.14 kept crashing. The build you sent have yet to crash. An running time of 4h without crashing sure isn't impressive, but it's miles beyond what I get on 3.14 (an album uninterrupted is a longshot). The original issue of skipping is unchanged on this older build.

[RockBoxOx]

I have this problem but I don't have any album artwork in my files. They were also encoded via Foobar using Opus 1.3

[Bilgus]

This needs testing to make sure it doesn't break anything else but should fix the issue

http://gerrit.rockbox.org/r/#/c/2046/