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Senior
Jul 15, 2025 8:31 AM UTC
Question

STM32N6 VENC at lower resolutions

Hi everyone,

I have successfully deployed the VENC_SDCARD example on the board and can see its feed on my laptop. Now, I want to record it at 480x480 resolution instead of the default 800x480 provided in the example.

I have modified the buffer size, DCMIPP, LTDC configurations, and made a few additional changes. I’m attaching my main.c and stm32n6570_discovery_lcd.c files for your reference.
The following is my camera feed.
Image (1).jpeg

and these are the debug statements in the uart terminal.

Screenshot from 2025-07-15 13-41-14.png

which looks fine to me with no errors.

However, after recording in microSD card and decoding using the ffmpeg command provided in the project's README, I get the following error:

kartikkhandewal@atl-hpzg14-99:~$ ffmpeg -f h264 -framerate 30 -i dump.bin -vf "fps=30" -c:v libx264 -preset veryfast -crf 23 output_fixed.mp4
ffmpeg version 4.4.2-0ubuntu0.22.04.1 Copyright (c) 2000-2021 the FFmpeg developers
 libavutil 56. 70.100 / 56. 70.100
 libavcodec 58.134.100 / 58.134.100
 libavformat 58. 76.100 / 58. 76.100
 libavdevice 58. 13.100 / 58. 13.100
 libavfilter 7.110.100 / 7.110.100
 libswscale 5. 9.100 / 5. 9.100
 libswresample 3. 9.100 / 3. 9.100
 libpostproc 55. 9.100 / 55. 9.100
[h264 @ 0x5c585e5063c0] pps_id 3199971767 out of range
[h264 @ 0x5c585e5063c0] non-existing PPS 0 referenced
 Last message repeated 6 times
[h264 @ 0x5c585e5063c0] pps_id 1206 out of range
[h264 @ 0x5c585e5063c0] non-existing PPS 0 referenced
[h264 @ 0x5c585e5063c0] decode_slice_header error
[h264 @ 0x5c585e5063c0] no frame!
|
- - - - - -
|
 Last message repeated 1 times
[h264 @ 0x5c585e5063c0] decode_slice_header error
[h264 @ 0x5c585e5063c0] no frame!
[h264 @ 0x5c585e4fc340] Stream #0: not enough frames to estimate rate; consider increasing probesize
[h264 @ 0x5c585e4fc340] decoding for stream 0 failed
[h264 @ 0x5c585e4fc340] Could not find codec parameters for stream 0 (Video: h264, none): unspecified size
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, h264, from 'dump.bin':
 Duration: N/A, bitrate: N/A
 Stream #0:0: Video: h264, none, 30 fps, 30 tbr, 1200k tbn, 60 tbc

So how should I proceed from here? Do I need to change some parameters in the VENC function?
Kindly help.

This topic has been closed for replies.

3 replies

athern27Author
Senior
Jul 15, 2025 10:55 AM UTC

Can someone move this topic to STM32 MCUs Products forum
I think it's more appropriate there.

athern27Author
Senior
Jul 21, 2025 9:58 AM UTC

Any updates regarding this

ST Employee
Jul 21, 2025 11:56 AM UTC

Hi,

 

This example was intended to be simple but, unfortunately, it was also hardcoded.

Please find attached a slightly modified version.

I tested it successfully with a resolution of 480x480.

Hope this helps.

 

Daniel