A bit slower fps and lower video% with remap
hevc-> av1_qsv
==============
# remap_video_decoder mpeg2video=mpeg2_qsv
Settings|Preferences|Performance|Use HW Device:
none
intel_gpu_top Video: up to 25%
** rendered 5972 frames in 22.474 secs, 265.729
fps
audio0 pad 64 0 (64)
----------------
remap_video_decoder mpeg2video=mpeg2_qsv
Settings|Preferences|Performance|Use HW Device:
none
intel_gpu_top Video: up to 23%
** rendered 5972 frames in 26.549 secs, 224.943
fps
audio0 pad 64 0 (64)
A renewed test example:
av1_qsv
========
Settings|Preferences|Performance|Use
HW Device: none
Decoding in GPU after remap
remap_video_decoder
mpeg2video=mpeg2_qsv
239-291 fps
-----------
Settings|Preferences|Performance|Use
HW Device: vaapi
Decoder mpeg2_qsv does not support
device type vaapi.
HW device init failed, using SW
decode.
file:/Videoklipp/AV1/hdv09_04.m2t
err: Operation not permitted
......
Render::render_single: Session
finished.
** rendered 5972 frames in 20.875
secs, 286.084 fps
audio0 pad 64 0 (64)
malloc_consolidate(): unaligned
fastbin chunk detected
Aborted (core
dumped) cin
===============
av1_qsv
========
Settings|Preferences|Performance|Use
HW Device: none
Decoding in CPU before remap
# remap_video_decoder
mpeg2video=mpeg2_qsv
Render::render_single: Session
finished.
** rendered 5972 frames in 20.001
secs, 298.585 fps
audio0 pad 64 0 (64)
----------
Settings|Preferences|Performance|Use
HW Device: vaapi
Decoding in cpu before remap
# remap_video_decoder
mpeg2video=mpeg2_qsv
int
FFVideoConvert::convert_picture_vframe(VFrame*,
AVFrame*, AVFrame*):
Error retrieving data from GPU to CPU
file: /Videoklipp/AV1/hdv09_04.m2t
Render::render_single: Session
finished.
** rendered 5972 frames in 30.432
secs, 196.241 fps
audio0 pad 64 0 (64)
Decoder libdav1d does not support
device type vaapi.
HW device init failed, using SW
decode.
file:/Videoklipp/QSV/hdv09-04_cin_av1_qsv_8b420.mp4
err: Operation not permitted
Decoder libdav1d does not support
device type vaapi.
HW device init failed, using SW
decode.
file:/Videoklipp/QSV/hdv09-04_cin_av1_qsv_8b420.mp4
err: Operation not permitted
>
>> Decoder mpeg2_qsv does not
support device type vaapi.
>> HW device init failed, using
SW decode.
>> file:/Videoklipp/AV1/hdv09_04.m2t
>> err: Operation not
permitted
>> ......
>> Render::render_single:
Session finished.
>> ** rendered 5972 frames in
20.875 secs, 286.084 fps
>> audio0 pad 64 0 (64)
>> malloc_consolidate():
unaligned fastbin chunk detected
>> Aborted
(core dumped) cin
>>
>> -------
>>
>> Yeah, of course Cingg and
ffmpeg are not comparable with regards
to video format transcoding speed..
>>
>> I guess their working
principles, surely oversimplified, may
be something like this example:
>>
>> Cingg: mpeg2 input -->
decoding -->internal/raw format
--> decoding?--> encoding output
>>
>> FFmpeg: mpeg2 input -->
decoding --> encoding output
>>
>>
>> Therefore it's confusing
where "remap_video_decoder
mpeg2video=mpeg2_qsv" decoding really
should take place, from mpeg2 input
--> internal/raw format rather than
decoding before encoding output?
> somewhere inside libavcodec ...
>
>
>>
>>
>>
>>
>> On Sun, Mar 8, 2026 at
11:46 PM Terje J. Hanssen via Cin
>> <cin@lists.cinelerra-gg.org>
wrote:
>>
>> I have tested transcoding
mpeg2video to h264_qsv, hevc_qsv,
vp9_qsv and
>> av1_qsv HW GPU accelerated
decoding+encoding with ffmpeg.
>> Just by adding "-hwaccel qsv"
before the input file, the correct qsv
>> codec for decoding in GPU
apparently is auto-detected.
>>
>> ffmpeg -hide_banner -hwaccel
qsv -i hdv09_04.m2t -c:v hevc_qsv -y
>> hdv09_04_ffmpeg_hevc_qsv.mp4
>>
>> With a medium powerful
(balanced) Intel Alder Lake
(i7-12700KF) /DG2
>> (A750) the qsv.mp4 video
output and playback are clean and
faster with
>> GPU decoding.
>> For the legacy, limited
SkyLake (h264_qsv) and Coffee Lake
(hevc_qsv)
>> igpu's, it is best to keep
decoding in CPU, due to igpu buffer
errors
>> and some distortions on the
playback.
>>
>>
>> So I wonder if it manageable
to test-implement an additional
environment
>> variable "CIN_HW_DEV=qsv" for
GPU HW decoding that adds "-hwaccel
qsv"
>> on the input side?
>> If it works, it may be added
as a "Use HW Device: qsv" next.
>>
>> Terje J. H
>>
>>
>>
>>
>>
>>
>>
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>> To unsubscribe send an email
to cin-leave@lists.cinelerra-gg.org
>>
>>
>>
>>
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