Unsupported framebuffer format

[bubak]

Hi all,

I've made a new recipe, but when trying to open the result with ebook-viewer, it says a lot of

QOpenGLFramebufferObject: Unsupported framebuffer format.
QOpenGLFramebufferObject: Framebuffer incomplete, missing attachment.
[2360464:2360489:1121/113314.186187:ERROR:gles2_cmd_decoder.cc(5797)] GLES2DecoderImpl::ResizeOffscreenFramebuffer failed because offscreen FBO was incomplete.
[2360464:2360489:1121/113314.186202:ERROR:gles2_cmd_decoder.cc(4023)] ContextResult::kFatalFailure: Could not allocate offscreen buffer storage.

Running the recipe itself did not produce any unusual messages. Anyone knows what the problem can be?

Cheers,

Bubak

[kovidgoyal]

The GPU drivers on your system are broken/too old. You can try turning off hardware acceleration as described here: https://doc.qt.io/qt-5/qtwebengine-debugging.html

[bubak]

Thanks, I've updated my debian testing and the problem is gone :-)

[bubak]

Alas, that was too quick a reply: I can now fetch the news and open it in calibre's ebook-viewer, but when I try to open it in my voyage, it says "Error". Is there a way to debug that? When I convert the mobi to epub and back, then I can open it in the voyage, however only for sequential reading, no article menu is shown.

[kovidgoyal]

There is no way to debug issues on Kindles. And roundtripping it will remove kindle specific periodic formatting.

[bubak]

Yes, but the mobi created from the recipe has obviously a problem, is it possible to analyze it? Like, is there a description of the mobi format available?

[kovidgoyal]

no, there isnt. It's a reverse engineered format. And I have never heard of a kindle having an issue with a calibre created mobi in over a decade. Most likely either the kindle is failing or the file was damaged during transfer.

[bubak]

I'm downloading 25+ news recipes each day to two kindles and have no problems with any of them, just this new one makes an error, so occam's rasor tells us it is this last recipe and not hardware or transfer :-) I've tried to generate azw3 instead of mobi, just to see if it would be any better, is that possible? When I change in Preferences/Behavior/Preferred output format to azw3, the download still produces mobi, is this setting somewhere else?

[kovidgoyal]

azw3 does not support periodical formatting either. If you want periodical formattingona kindle, it has to be mobi

[bubak]

I see. I've played a little bit more with the recipe a got it to work. The bad guy was

<div class="g_bv" data-dot="mol-embed">
<div class="e_bu e_f e_k e_j mol-embed__iframe">
<div class="e_hP e_k" style="padding-top:81.17469879518072%">
</div>
</div>
</div>

which created a large empty gap in the output files.

[bubak]

Well, that was too fast :-( After a couple of days, the problem has reappeared, the MOBI file is created ok and it can be ebook-viewed but it makes an error in my Kindle. What is quite strange: I use ebook-convert --test to load 2 articles from this source, convert the resulting MOBI to EPUB and back and the resulting MOBI still causes an error, i.e. the problem is already present in the EPUB file. Kovid, do you think that you could find what's wrong with the file if I sent you the EPUB?

[kovidgoyal]

No, the only way to know what the kindle doesnt like is to delete things from the book, convert, re-upload to kindle, test. Waaaaay too much work.

[bubak]

Fair enough. Done that and (at least for now) it seems that the culprit was the cover_url = 'https:/...' image. Somehow I think that the guys behind this news source do not want us to download it, that's why I'm not quoting the link here :-)