[Android] [RFC PATCH 0/2] Use HW Decoders before Android 4.3 for a list of known devices

[Martin Storsjö]

On Tue, 7 Oct 2014, Thomas Guillem wrote:

> Hi there,
>
> I added a utility class that contains a list of devices that are known to work
> with MediaCodec and/or OMX before android 4.3. The list is not exhaustive, and
> it would be great if some other developers add some devices on that list.
>
> So, when we are in automatic decoder mode (by default), either we use
> MediaCodec if Android version >= 4.3 or we use HWDecoderUtil to get the best
> decoder for that device (with HW_ACCELERATION_FULL flag).
>
> I also use that table when user force HW Decoder from the menu. So if someone
> force HW decoder on a device that is blacklisted, it won't try any HW Decoders.
> And if someone force HW Decoder on a device that is known to work only on OMX,
> it won't try MediaCodec.
>
> My main issue is that iomx will be more used (see the list), and I only tested
> OMX with direct rendering (I can't test anymore since I don't have these
> devices anymore). By the way, I think that iomx-dr is more reliable than iomx.

Yes, iomx-dr is probably more reliable than normal iomx.

Also, most of your test results was with a different codebase, right? So 
there might still be corner cases where iomx-dr _should_ work but doesn't 
due to some other missing cornercase.


One consequence for developers is that they need to hack this out whenever 
they want to e.g. try fixing issues in the iomx/mediacodec decoders on 
devices where it's disabled in the automatic codepaths (or want to try to 
make mediacodec work on a device that only tries to use iomx). This is not 
an objection but mostly a mental note, because I'm sure I'll forget it at 
some point...

> So, I'm not sure if we should use these patches for 1.0 (that use vlc 2.2
> branch without iomx-dr), or if we should push iomx-dr patches into 2.2. I don't
> know, it's a big change just before a release...

Indeed, it's a big change and I haven't followed all the policies about 
cherrypicking into release branches, but without iomx-dr it's not much 
point in autoenabling iomx at all, I'd say.

// Martin