[FFmpeg-devel] [PATCH 2/2] lavc: add h264 mediacodec decoder

[Matthieu Bouron]

On Tue, Feb 23, 2016 at 11:28:01AM +0100, wm4 wrote:
> On Tue, 23 Feb 2016 09:53:43 +0100
> Matthieu Bouron <matthieu.bouron at gmail.com> wrote:
> 
> > On Mon, Feb 22, 2016 at 01:08:49PM +0100, Michael Niedermayer wrote:
> > > On Mon, Feb 22, 2016 at 12:20:36PM +0100, Matthieu Bouron wrote:  
> > > > From: Matthieu Bouron <matthieu.bouron at stupeflix.com>  
> > > [...]  
> > > > +        codec = (*env)->NewObject(env, jfields.mediacodec_list_class, jfields.init_id, 0);
> > > > +        if (!codec) {
> > > > +            av_log(NULL, AV_LOG_ERROR, "Could not create media codec list\n");
> > > > +            goto done;
> > > > +        }
> > > > +
> > > > +        tmp = (*env)->CallObjectMethod(env, codec, jfields.find_decoder_for_format_id, format);
> > > > +        if (!tmp) {
> > > > +            av_log(NULL, AV_LOG_ERROR, "Could not find decoder in media codec list\n");
> > > > +            goto done;
> > > > +        }
> > > > +
> > > > +        name = ff_jni_jstring_to_utf_chars(env, tmp, NULL);
> > > > +        if (!name) {  
> > >   
> > > > +            av_log(NULL, AV_LOG_ERROR, "Could not convert jstring to utf chars\n");  
> > > 
> > > some non NULL context would be better, if possible, so the user knows
> > > where an error came from  
> > 
> > It would require to pass the log_ctx (avctx) as an argument of
> > ff_AMediaCodecList_getCodecByName.
> > 
> > All the functions of this wrapper does not take a log_ctx as argument
> > to be as close as possible to the original NDK MediaCodec API. The
> > NDK MediaCodec API does not provide any wrapper around MediaCodecList.
> > 
> > I would like the whole wrapper API to be consistent but also as close as
> > possible to original one.
> > If you think it's mandatory I can add a log_ctx argument to every
> > functions of the wrapper API (so it will be used directly by av_log and
> > ff_jni_exception_check).
> > 
> > On another note, I fixed locally this part of the code by adding missing calls
> > to ff_jni_exception_check.
> > 
> > [...]
> 
> Is it possible to store the log_ctx somewhere in the JNI?
> 
> We might at some point in the future forbid av_log(NULL, ...) calls, and
> then it'd get complicated.

Patch updated with the following differences:
  * All logging arguments in mediacodec_wrapper functions are now non
  NULL
  * The mediacodec buffer copy functions has been moved to a separate file
  * The Mediacodec enum codec flags are properly retrieved from JNI

The codec extradata conversion to annex b simplification has not been
addressed in this update. The bitstream filter api does not seem to
provide a way to do the extradata conversion without feeding an actual
packet to the api (av_bitstream_filter_filter) and i would like to keep
the codec initialization in the init function.

The patchset has been pushed to a new branch:
https://github.com/mbouron/FFmpeg/tree/feature/mediacodec-support-v3

Matthieu
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