On 11/03/2026 13:17, Andrew Randrianasulu wrote:
> On Wed, Mar 11, 2026 at 2:14 PM Terje J. Hanssen via Cin
> <cin@lists.cinelerra-gg.org> wrote:
>>
>>
>> On 10/03/2026 01:34, Andrew Randrianasulu wrote:
>>
>> On Mon, Mar 9, 2026 at 7:22 PM Terje J. Hanssen <terjejhanssen@gmail.com> wrote:
>>
>> On 09/03/2026 11:28, Andrew Randrianasulu wrote:
>>
>> You need to set remappig manually in  (for single-user buld)
>>
>> bin/ffmpeg/decode.opts
>>
>> like
>>
>> remap_video_decoder mpeg2video=mpeg2_qsv
>>
>> and other similar lines if you want to test other formats (hevc, h264)
>>
>> Thank you for quick response.
>> After editing:
>>
>> ~/Applications/squashfs-root/usr/bin/ffmpeg # cat decode.opts
>> # apply at init decode
>> loglevel=fatal
>> formatprobesize=5000000
>> scan_all_pmts=1
>> remap_video_decoder libaom-av1=libdav1d
>> remap_video_decoder mpeg2video=mpeg2_qsv
>>
>> Compilation of my test results as follows:
>>
>> mpeg2 transcoded to h264_qsv.mp4
>>
>> decoding in cpu/gpu
>> Cingg:  265/300 fps
>> ffmpeg: 548/562 fps
>>
>>
>> mpeg2 transcoded to hevc_qsv.mp4
>>
>> decoding in cpu/gpu
>> Cingg:  290/294 fps
>> ffmpeg:  - /688 fps
>>
>>
>> mpeg2 transcoded to av1_qsv.mp4
>>
>> decoding in cpu/gpu
>> Cingg:  251/325 fps
>> ffmpeg: 631/698 fps
>>
>>
>> As seen the Cingg fps results are much slower than my system ffmpeg results.
>> Is there any way to verify that decoding is done in the gpu like with ffmpeg?
>>
>> Comment out remap line and retest? Watch nvtop or "intel gpu top"  not
>> sure if they discriminate between enc and decoding on Intel (it works
>> on amd polaris12)?
>>
>> As I said earlier we are not even supposed to be as fast as ffmpeg in
>> ideal case because we roundtrip uncompressed video via system
>> memory/bus.
>>
>>
>> I tried intel_gpu_top which has a video line (for total gpu use in % I think).
>>
>> At least Cingg HW use device seemingly will output in the terminal if it is not supported as for:
>>
>> Settings|Preferences|Performance|Use HW Device: vaapi
> Does it work better if you set Use hw device to none ?

Yes, as the previous results above, decoding cpu/gpu (before remap/after
remap)
But no speed benefit to set remap, results just within variations from
time to time

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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>>
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