[FFmpeg-trac] #7943(undetermined:new): Ffmpeg QSV backend uses >2x more GPU memory compared to VAAPI or MSDK
FFmpeg
trac at avcodec.org
Wed Oct 16 12:48:23 EEST 2019
#7943: Ffmpeg QSV backend uses >2x more GPU memory compared to VAAPI or MSDK
-------------------------------------+-------------------------------------
Reporter: eero-t | Owner:
Type: defect | Status: new
Priority: normal | Component:
| undetermined
Version: git-master | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by fulinjie):
This seems to be similar with the performance gap issue #7690.
There is an internally memory allocation and memory copy in MSDK core
library(may not be involved in sample_multi_transcode),
CommonCORE::DoFastCopyExtended
https://github.com/Intel-Media-
SDK/MediaSDK/blob/master/_studio/shared/src/libmfx_core.cpp#L1522
Thus the memory usage is twice large.
https://github.com/Intel-Media-
SDK/MediaSDK/issues/1550#issuecomment-515417010
It could be verified by gpu_copy decode which do not allocate memory
internally:
Allocate memory internally:
ffmpeg -y -hwaccel qsv -qsv_device /dev/dri/renderD128 -c:v hevc_qsv -an
-i SES.Astra.UHD.Test.1.2160p.UHDTV.AAC.HEVC.x265-LiebeIst.mkv -vf
hwdownload,format=p010 -f rawvideo /dev/null
ffmpeg: 155 objects, 1680379904 bytes
1.6 GB
No memory allocation internally with gpu_copy:
ffmpeg -y -qsv_device /dev/dri/renderD128 -gpu_copy on -c:v hevc_qsv -an
-i SES.Astra.UHD.Test.1.2160p.UHDTV.AAC.HEVC.x265-LiebeIst.mkv -f rawvideo
/dev/null
ffmpeg: 140 objects, 393277440 bytes
400 MB
The memory gap is obvious.
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Ticket URL: <https://trac.ffmpeg.org/ticket/7943#comment:1>
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