rpi-hevc-dec hang

[chep]

Describe the bug

I'm trying to play an mkv file with gstreamer and v4l2slh265dec. It always hang when decoding frame 579.

I kept the video file so I can send it for debug.

Steps to reproduce the behaviour

• Ask me for the video file
• Start gstreamer gst-launch-1.0 filesrc location=output.mkv ! matroskademux ! h265parse ! queue ! v4l2slh265dec ! queue ! fakevideosink

Device (s)

Raspberry Pi CM5

System

I use nixos.

[pulsar@pulsar-RC:~]$ uname -a
Linux pulsar-RC 6.12.87 #1-NixOS SMP Tue Jan 1 00:00:00 UTC 1980 aarch64 GNU/Linux

[pulsar@pulsar-RC:~]$ vcgencmd version
2025/06/13 10:39:26
Copyright (c) 2012 Broadcom
version 5855b10b (release) (embedded)

Logs

gst-launch-1.0 filesrc location=output.mkv ! matroskademux ! h265parse ! queue ! v4l2slh265dec ! queue ! autovideosink
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
Got context from element 'autovideosink0': gst.gl.GLDisplay=context, gst.gl.GLDisplay=(GstGLDisplay)"\(GstGLDisplayWayland\)\ gldisplaywayland0";
Redistribute latency...
Redistribute latency...
Redistribute latency...
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
Redistribute latency...
New clock: GstSystemClock
ERROR: from element /GstPipeline:pipeline0/v4l2slh265dec:v4l2slh265dec0: Decoding frame 579 took too long
Additional debug info:
../sys/v4l2codecs/gstv4l2codech265dec.c(1293): gst_v4l2_codec_h265_dec_output_picture (): /GstPipeline:pipeline0/v4l2slh265dec:v4l2slh265dec0
Execution ended after 0:00:11.608416910
Setting pipeline to NULL ...
ERROR: from element /GstPipeline:pipeline0/GstMatroskaDemux:matroskademux0: Internal data stream error.
Additional debug info:
../gst/matroska/matroska-demux.c(6360): gst_matroska_demux_loop (): /GstPipeline:pipeline0/GstMatroskaDemux:matroskademux0:
streaming stopped, reason error (-5)
Details:
details, flow-return=(int)-5;
ERROR: from element /GstPipeline:pipeline0/GstQueue:queue0: Internal data stream error.
Additional debug info:
../plugins/elements/gstqueue.c(1081): gst_queue_handle_sink_event (): /GstPipeline:pipeline0/GstQueue:queue0:
streaming stopped, reason error (-5)
Details:
details, flow-return=(int)-5;

Process is stuck:

pulsar      1449  0.3  0.9 917936 79488 pts/0    Dl+  13:04   0:00 /run/current-system/sw/bin/gst-launch-1.0 filesrc location=output.mkv ! matroskademux ! h265parse ! queue ! v4l2slh265dec ! queue ! autovideosink

Here is dmesg output:

[  729.112502] rpi-hevc-dec 1000800000.codec: Col ref index 255 >= 0

Additional context

No response

[popcornmix]

Can you upload a sample video file (e.g. to google drive) that exhibits the issue?
Ideally cut it to a short sample (e.g. under a minute) that shows the issue.

[6by9]

Where have you got a version of GStreamer from that supports the pixel format from the HEVC decoder? Which version of GStreamer are you using?
There are patches merged to the Pi OS Trixie repos to add GStreamer support, but only to work against the 6.18 or later kernels.

The latest version of the kernel decoder driver is only in 6.18, and as part of the upstreaming process there were a few things that changed in the understanding of parameters to then match GStreamer. I don't know of a version of v4l2slh265dec that works with 6.12.

[chep]

Here is a small video file : https://drive.google.com/file/d/15vz8im4X4vezmmkkaIoBIhH9CKgCVOdA/view?usp=sharing

[chep]

Where have you got a version of GStreamer from that supports the pixel format from the HEVC decoder? Which version of GStreamer are you using? There are patches merged to the Pi OS Trixie repos to add GStreamer support, but only to work against the 6.18 or later kernels.

The latest version of the kernel decoder driver is only in 6.18, and as part of the upstreaming process there were a few things that changed in the understanding of parameters to then match GStreamer. I don't know of a version of v4l2slh265dec that works with 6.12.

I started here: https://github.com/nvmd/nixos-raspberrypi and then built my system. I'll try with 6.18

[6by9]

Here is a small video file : https://drive.google.com/file/d/15vz8im4X4vezmmkkaIoBIhH9CKgCVOdA/view?usp=sharing

Reproduced on Pi OS (GStreamer 1.26.2) with 7.2 kernel (identical to 6.18 other than a very minor API change).
Same rpi-hevc-dec feb00000.codec: Col ref index 255 >= 0 error logged.

@jc-kynesim This looks like it is something invalid in the stream, but it takes out the decoder.
This is vaguely familiar from a conversation a few weeks back where userspace is trying to skip frames and passing in deliberately invalid reference frame indices.

[jc-kynesim]

Yeah - probably is the same - works fine in ffmpeg which is a little nicer to the decoder. Thought I'd fixed it - I'll check.

[6by9]

Yeah - probably is the same - works fine in ffmpeg which is a little nicer to the decoder. Thought I'd fixed it - I'll check.

It's possibly not been merged yet.
I haven't attacked your updates recently to create the next revision for upstream.

[jc-kynesim]

Yup - it is fixed in my to-be-upstreamed branch (dev/6.18/hevc_dec_8) but not rpi-6.18.y. I can rebuild the branch onto 7.2 if that is currently usable?

[6by9]

I only happened to use 7.2.0-rc1 as that was what I had to hand. I wouldn't recommend anyone trying to use it in anger until it is released.

6.18 is still our main kernel.

I'll do a squash of all those and make a PR to rpi-6.18.y. They'll be squashed into the main driver patch before upstreaming anyway, so the history is only really there for my review benefit.

[jc-kynesim]

N.B. There's a patch (hevc_d: Remove clock frequency setting code (Maira)) in there that removes the code that does clock rate setting which is definitely correct for upstream, but might not be correct for us possibly also depends on what doms new clock code does.

[6by9]

PR #7481 pulls in the latest changes (except the clock ones).

[pelwell]

All together now: You can install a trial build of that kernel using sudo rpi-update pulls/7481, but read the caveats first.