[FFmpeg-devel] [PATCH 10/12] avcodec: add MediaCodec encoder

["zhilizhao(赵志立)"]

> On Oct 27, 2022, at 17:56, Tomas Härdin <git at haerdin.se> wrote:
> 
> tor 2022-10-27 klockan 10:49 +0800 skrev zhilizhao(赵志立):
>> 
>> 
>>> On Oct 27, 2022, at 05:17, Tomas Härdin <git at haerdin.se> wrote:
>>> 
>>> mån 2022-10-24 klockan 11:16 +0800 skrev Zhao Zhili:
>>>> 
>>>> +typedef struct MediaCodecEncContext {
>>>> +    AVClass *avclass;
>>>> +    FFAMediaCodec *codec;
>>>> +    int use_ndk_codec;
>>>> +    FFANativeWindow *window;
>>>> +
>>>> +    int fps;
>>>> +    int width;
>>>> +    int height;
>>>> +
>>>> +    uint8_t *extradata;
>>>> +    int extradata_size;
>>> 
>>> Why not extradata in AVCodecContext?
>> 
>> The extradata (BUFFER_FLAG_CODEC_CONFIG) is popped after codec
>> init, I’m not sure if it’s OK to touch AVCodecContext->extradata
>> after code init.
> 
> You mean that it isn't populated until after a frame has been encoded?
> There's no way to specify resolution, pixel format etc to get the
> extradata without encoding?

That’s the case from my test on Google Pixel 3. There is no ‘csd’ inside
MediaFormat returned by ff_AMediaCodec_getOutputFormat(), until a frame
has been sent. It may depends on the device and OS.

> 
>> Secondly, it isn’t specified in Android doc, but better be safe
>> to handle the case of BUFFER_FLAG_CODEC_CONFIG show up multiple
>> times.
> 
> Surely there's a way to signal this? I suppose one can always add a bsf
> after the encoder. I'm actually not sure.

We can use AV_PKT_DATA_NEW_EXTRADATA to signal that along with
AVCodecContext->extradata. We still need to save extradata to a place
other than AVCodecContext->extradata temporarily.

>> 
> 
>>> Some tests would be nice
>> 
>> Did you mean fate test or manual test?
>> 
>> It’s an external codec wrapper, so maybe not in fate.
> 
> It would be nice if FATE could test this on machines where the hardware
> is available. We had a brief discussion on IRC about this yesterday.
> Just checking which encoders actually work, what profiles are supported
> and so on. Maybe tabulate it somewhere. Sometimes manufacturers specify
> what codecs and profiles are supported, sometimes not.

I’m planing to add more options for codec configure and select codec by
name. Run FATE on Android is doable.

> 
> /Tomas
> 
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