> -----Original Message----- > From: ffmpeg-devel [mailto:ffmpeg-devel-boun...@ffmpeg.org] On Behalf Of > Mark Thompson > Sent: Wednesday, April 10, 2019 6:27 AM > To: ffmpeg-devel@ffmpeg.org > Subject: Re: [FFmpeg-devel] [PATCH RFC v2 2/3] libavcodec: Add thumbnail > output to vaapi_h264 decoder > > On 08/04/2019 09:53, Zachary Zhou wrote: > > This is sample code for reference > > > > HW support for decode+scaling in a single HW command (VDBOX+SFC). > > The primary target usage is video analytics, but can be used playback, > > transcoding, etc. > > > > For VAAPI - > > https://github.com/intel/libva > > basically, it allows multiple outputs (in different resolutions) using the > decode context in a single call (you can search for “additional_outputs” in > va.h). > > > > VAAPI sample code - > > https://github.com/intel/libva-utils/commit/957a269f02b00760b7e807643c > > 821ee26abc529b > > --- > > libavcodec/avcodec.h | 8 +++ > > libavcodec/decode.c | 16 +++++ > > libavcodec/options_table.h | 4 ++ > > libavcodec/vaapi_decode.c | 122 > > ++++++++++++++++++++++++++++++++++--- > > libavcodec/vaapi_decode.h | 30 +++++++++ > > libavcodec/vaapi_h264.c | 13 ++++ > > 6 files changed, 185 insertions(+), 8 deletions(-) > > This doesn't fit into the libavcodec API at all. If it is desirable to have > some > sort of generic multiple-output mechanism in libavcodec, please open a > separate discussion considering that API specifically. > > For the particular hardware instance you are talking about here, can you > explain what this mechanism actually helps with? My understanding was that > the VDBOX / SFC chaining existed to save a small amount of power in > restricted playback cases going directly to the display (that is, for > maximising > playback time on battery devices). Since you are writing everything back to > memory immediately here anyway, I don't see how it helps compared to just > doing the scale as a filter operation. > > - Mark
Thanks Mark, I understand it doesn't fit the libavcodec API currently, and I will open a discussion regarding multiple-output mechanism in libavcodec. you may already know following document - https://01.org/sites/default/files/documentation/intel-gfx-prm-osrc-skl-vol15-sfc.pdf As my investigation - - This feature can save some power and memory bandwidth. - This feature can save the ffmpeg filters code writing for end user. it also support ARGB output for some AI use case, I think some AI cases may need ARGB input. -Zach > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org > with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
