Feedback below:

AOM-SVT:

$ ffprobe -hide_banner test_aom_svt.webm
[libdav1d @ 0x55b740a0a140] libdav1d 1.3.0
Input #0, matroska,webm, from 'test_aom_svt.webm':
  Metadata:
    ENCODER         : Lavf60.16.100
  Duration: 00:01:12.17, start: 0.000000, bitrate: 1369 kb/s
  Stream #0:0: Video: av1 (Main), yuv420p(pc,
bt2020nc/unknown/unknown, progressive), 1920x1080, SAR 1:1 DAR 16:9,
24 fps, 24 tbr, 1k tbn
    Metadata:
      DURATION        : 00:01:12.128000000
  Stream #0:1(ita): Audio: vorbis, 48000 Hz, stereo, fltp
    Metadata:
      DURATION        : 00:01:12.170000000
[libdav1d @ 0x55b740a46400] libdav1d 1.3.0

(11.8 MB; 58 fps)

The video, but especially the audio, seem to me to be of slightly
lower quality than the original sources.

> If SVT-AV1 1.8.0 rendering is possible with cin-aom-38_svt.AppImage, where do you select this?
Among the webm presets should also appear av1-svt.webm, the profile
created by Andrew; see image:

Am I the only one getting errors when rendering using av1-svt.webm (video only) as shown in bold below? or am I doing something wrong?

Cinelerra is free software, covered by the GNU General Public License,                    
and you are welcome to change it and/or distribute copies of it under                    
certain conditions. There is absolutely no warranty for Cinelerra.                        

Svt[info]: -------------------------------------------                                    
Svt[info]: SVT [version]:       SVT-AV1 Encoder Lib v1.8.0                                
Svt[info]: SVT [build]  :       GCC 10.3.1 20210422 (Red Hat 10.3.1-1)   64 bit          
Svt[info]: LIB Build date: Jan  1 2024 16:24:53                                          
Svt[info]: -------------------------------------------                                    
Svt[info]: Number of logical cores available: 16                                          
Svt[info]: Number of PPCS 76                                                              
Svt[info]: [asm level on system : up to avx2]                                            
Svt[info]: [asm level selected : up to avx2]                                              
Svt[info]: -------------------------------------------                                    
Svt[info]: SVT [config]: main profile   tier (auto)     level (auto)                      
Svt[info]: SVT [config]: width / height / fps numerator / fps denominator      :           1440 / 1080 / 30000 / 1001                                                              
Svt[info]: SVT [config]: bit-depth / color format                              :           8 / YUV420                                                                              
Svt[info]: SVT [config]: preset / tune / pred struct                           :           10 / PSNR / random access                                                                
Svt[info]: SVT [config]: gop size / mini-gop size / key-frame type             :           161 / 16 / key frame
Svt[info]: SVT [config]: BRC mode / rate factor                                : CRF / 35
Svt[info]: -------------------------------------------
Svt[warn]: Failed to set thread priority: Invalid argument
FFStream::encode_frame: encode failed.
file: /tmp/svt8.webm
  err: Resource temporarily unavailable
FFMPEG::mux_video  err: Operation not permitted
FFStream::encode_frame: encode failed.
file: /tmp/svt8.webm
  err: Resource temporarily unavailable
FFMPEG::mux_video  err: Operation not permitted
Render::render_single: Session finished.
** rendered 1656 frames in 25.363 secs, 65.292 fps
FFMPEG::open_decoder: some stream times estimated: /tmp/svt8.webm
FFMPEG::open_decoder: some stream times estimated: /tmp/svt8.webm