Re: [FFmpeg-devel] [Internet][PATCH v2 00/12] Add MediaCodec encoder and NDK MediaCodec support

[StreamNG Harold Camargo <haroldcamargo@stream-ng.com>]

please. unsuscribe.


Harold F. Camargo R.
Stream NG
Cel. 318 3227862
Bogotá Colombia
www.stream-ng.com


El lun, 21 nov 2022 a las 11:23, Zhao Zhili (<quinkblack@foxmail.com>)
escribió:

> On Sun, 2022-11-20 at 14:49 +0800, Zhao Zhili wrote:
> > From: Zhao Zhili <zhilizhao@tencent.com>
> >
> >
> > v2:
> >
> > Rebased on master.
> >
> > 01/12: Use crop-width/crop-height as fallback and add TODO. Co-
> > authored-by: Aman Karmani
> > 07/12: Fix libavcodec/version.h conflict
> > 10/12: Change default i-frame-interval to 1 and add log message; bump
> > minor version
> > 12/12: Fix rebase conflict
> >
> >
> > v1:
> > Firstly, some bugs were fixed (patch 1-4).
> >
> > Patch 5 and 6 make mediacodec_wrapper support Java MediaCodec and NDK
> > MediaCodec. The use case I'm considering is run FFmpeg on cmdline
> > without JVM,
> > for example, run FFmpeg inside of termux (an Android terminal
> > emulator). It's
> > well known that NDK MediaCodec missing some important functions, like
> > get the
> > list of codecs, but still useable.
> >
> > Patch 7 add NDK MediaCodec decoder support. It can be enabled via
> > options,
> > and enabled automatically if no JVM is available.
> >
> > Patch 8 add ANativeWindow support to hwcontext_mediacodec. It can be
> > set by
> > user, and can be created via AMediaCodec_createPersistentInputSurface
> > automatically. This is a preparation for encoder.
> >
> > Patch 9 makes MediaCodec decoder to support ANativeWindow directly.
> > It worth
> > to note that AVMediaCodecContext has only surface. Although we
> > provided
> > av_mediacodec_alloc_context(), we didn't strictly prevent users to
> > allocate
> > AVMediaCodecContext on stack. I'm not sure if it's OK to add new
> > field to
> > AVMediaCodecContext.
> >
> > Patch 10 add MediaCodec encoder support. Frame can be feed to encoder
> > via
> > buffer, or via Surface/ANativeWindow. If Surface/ANativeWindow is
> > used, and
> > the frames come from our MediaCodec decoder wrapper, we can control
> > it's
> > 'render' (send to encoder's surface) via
> > av_mediacodec_release_buffer(). A DTS
> > generation strategy works in this case. However, if frames comes from
> > other
> > sources, like a camera, there is no way to control the 'render' yet,
> > so DTS is
> > missing in this case.
> >
> > Finally, we can do mediacodec transcoding with FFmpeg cmdline on
> > Android.
> > More importantly, we can do MediaCodec decoder to encoder without
> > copy frames,
> > although it's very limited since most of avfilters doesn't work. For
> > example:
> >
> > ./ffmpeg -hwaccel mediacodec -hwaccel_output_format mediacodec -i
> > /sdcard/test.mp4 -an -c:v h264_mediacodec -y /sdcard/out.mp4
> >
> > Since there is no real AVHWFrameContext implementation in
> > hwcontext_mediacodec.
> > there is no hwframe_ctx for mediacodec and av_hwframe_transfer_data()
> > doesn't
> > work. So if -hwaccel_output_format isn't being specified like:
> >
> > ./ffmpeg -hwaccel mediacodec -i /sdcard/test.mp4 -an -c:v
> > h264_mediacodec -y /sdcard/out.mp4
> >
> > It will trigger a crash in av_hwframe_transfer_data. Patch 11 add a
> > check on
> > hwframe_ctx. Patch 12 set hwaccel_output_format automatically to
> > avoid such
> > case.
> >
>
> Applied.
>
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