[FFmpeg-devel] about mediacodec encoder on android platform

[156615797]

Hi,
Thanks for your reply let me know the reasons why using java wrapper instead of native apis.
These days I've already started the work of adding mediacodec encoder support.
And i also want to use the java wrappers, because I found the mediacodec_wrapper.c
wrapped funcations should also can be used by encoder. So, I think it will not be very
complicated and will not waste a lot of time to wrap the encoder needed java apis through jni.
and as you mentioned, the java apis can run on more devices .
My plan is to support surface input and plain buffer, may meet many problems,but i'll try it!
btw, you said Aman Gupta has already did the work switch to using ndk apis for decoder, 
i also want to get some information about that ,can you provide me the git address?
Thanks!


 原始邮件 
发件人: Martin Storsj<martin at martin.st>
收件人: FFmpeg development discussions and patches<ffmpeg-devel at ffmpeg.org>
发送时间: 2020年3月31日(周二) 16:46
主题: Re: [FFmpeg-devel] about mediacodec encoder on android platform


On Tue, 31 Mar 2020, Matthieu Bouron wrote: > On Fri, Mar 27, 2020 at 04:21:59PM +0800, aistoy wrote: >> Hi, I want to know why ffmpeg do not include mediacodec encoder, just include mediacodec decoder. >> And why the decoder implemention don’t use mediacodec native api, but use jni call mediacodec java methods. >> If i plan to add the mediacodec encoder, what do you think i should pay attention to ? > > Hi, > > Sorry for the late replay. > > The MediaCodec decoder wrapper in FFmpeg does not use the native API > because at the time it was implemented, more than 40% of the devices were > running Android 4.4 (which does not support the native API). > > The MediaCodec native API has also some limitation regarding codec > probing, ie: it does not provide a wrapper around > MediaCodecList/MediaCodecInfo. We use this capability to blacklist > software codecs for example. > > I made our MediaCodec java wrapper implement the same API as the native > one provided by the NDK so it shouldn't be too hard to switch. > Moreover, Aman Gupta already already did this work in one of his branches. > > The "tricky" part about implementing MediaCodec encoding support in FFmpeg > will be to fit the encoder input surface API into the libavcodec API. FWIW, one doesn't need to use the surface API for input to encoders. Since Android 4.3 they all support either YUV420 or NV12 as input via plain buffers (enforced via a CTS test), fairly quirk free actually. On Android 4.1 and 4.2 though, there were no tests that enforced encoders to behave, and they did pretty much whatever they wanted (having their own definitions of pixel formats, meaning something totally different to their standard names etc, with nonstandard padding). // Martin _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel at ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".