[FFmpeg-trac] #11352(avcodec:new): On the state of FFmpeg's ffv1_vulkan encoder implementation on Intel & NVIDIA

[FFmpeg]

#11352: On the state of FFmpeg's ffv1_vulkan encoder implementation on Intel &
NVIDIA
-------------------------------------+-------------------------------------
             Reporter:  Dennis E.    |                     Type:  defect
  Mungai                             |
               Status:  new          |                 Priority:  normal
            Component:  avcodec      |                  Version:  git-
             Keywords:  vulkan ffv1  |  master
  ffv1_vulkan                        |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 The subject matter above refers.
 Sample command-lines are provided for reference, see the notes section
 below.


 **(a). Intel:**

 {{{
 ffmpeg \
 -init_hw_device vulkan=vk:0 \
 -hwaccel vulkan -hwaccel_output_format vulkan \
 -hwaccel_device vk -filter_hw_device vk \
 -loglevel info \
 -fflags +genpts \
 -i '4KIOS.mov' \
 -vf "bwdif_vulkan,libplacebo=format=yuv420p" \
 -c:v ffv1_vulkan \
 -r:v 60 -g:v 2 -level:v 4 -strict -2 -coder:v 2 -context:v 1 \
 -c:a libfdk_aac -b:a 128k -ar 48000 -ac 2 \
 -map "0:v" -map "0:a" \
 -max_muxing_queue_size 8192 -max_interleave_delta 0 \
 -flags -global_header+cgop \
 -y -f matroska "ticketx_ffv1.mkv"
 }}}


 **(b). NVIDIA:**

 {{{
 ffmpeg \
 -init_hw_device vulkan=vk:0 \
 -hwaccel vulkan -hwaccel_output_format vulkan \
 -hwaccel_device vk -filter_hw_device vk \
 -loglevel info \
 -fflags +genpts \
 -i '4KIOS.mov' \
 -vf "bwdif_vulkan,libplacebo=format=yuv420p" \
 -c:v ffv1_vulkan \
 -r:v 60 -g:v 2 -level:v 4 -strict -2 -coder:v 2 -context:v 1 \
 -c:a libfdk_aac -b:a 128k -ar 48000 -ac 2 \
 -map "0:v" -map "0:a" \
 -max_delay 5000000 -max_muxing_queue_size 8192 -max_interleave_delta 0 \
 -flags -global_header+cgop \
 -y -f matroska "ticket4_ffv1.mkv"
 }}}


 **Runtime notes:**

 It's observed that the encoder also works quite well with and without
 using Vulkan H/W Accelerated decode, producing consistent results across
 multiple runs per test platform with and without Vulkan H/W Accelerated
 decode.

 As noted by Lynne on IRC regarding this encoder, handling yuv420p requires
 the following conditions to be met:
 i. Either 64 pixel aligned images for both h and v.
 ii. And using version 4 (Pass `-level 4 -strict -2`).

 The example commands above have the flags `-strict -2` and `-level:v 4`
 set to match the constraints defined above.

 **Oddities/bugs:**

 1. Even with identical parameters, the file sizes produced by Intel's and
 NVIDIA's `ffv1_vulkan` instances differ significantly.
 Intel's anv driver produces ridiculously massive files as shown below:
 The file from NVIDIA's session,named "ticket4_ffv1.mkv" is about 4.9G in
 size.
 Intel's session output with the same settings, named "ticketx_ffv1.mkv",
 weighs at 41 GB.

 2. NVIDIA's performance with this encoder, as tested on the RTX 4060 Max Q
 with a 4k input sample is at about ~0.63x speed.
 Intel's performance on the Integrated Raptor Lake GPU with the ANV driver
 clocks in at a paltry speed of 0.0907x. 7x slower.

 3. With NVIDIA, the {{{ffv1_vulkan encoder}}} will hang at a sporadic
 frame on each session *if* `-g:v` is higher than 2, regardless of the
 `-level:v` setting, all else being constant.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11352>
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