AW: "broken/invalid nal" with h264parse after v4l2h264enc on i.MX6

[Maurer, Marie]

Hi Nicolas,

many thanks for your answer. I am currently building Gstreamer 1.14.4 (and some more). When it is done, I can retest.
We don't use Yocto, but I had not yet locally updated to 1.14.4.

The complete pipeline is big, but I think I can reduce it to following overview (queue, caps removed, where not explicitly needed):

appsrc -> tee T1

T1 -> v4l2h264enc -> tee T2

T2#1 -> "Streaming"

T2#2 -> ("Video Recording to a file") h264parse -> CAPS streaming-format=avc -> ...

Video Recording to a file contains the h264parse, which reports these warnings.

We attach v4l2h264enc (to T1) only when streaming and/or video recording is enabled to save resources
and detach it when both are switched off.
We attach streaming (to T2) only, when it is enabled and detach it when streaming is disabled.
We attach "video recording to a file" (also to T2) only when user wants it and detach it when user switches it off.
At T1 we have more parts connected, which consume frames.

The main problem I have (beside the reported warnings) is that sometimes, h264parse and following caps can't be linked.

!!!Speculation!!!
This could be, but I am not sure yet, that h264parse reports streaming-format=byte-stream, which does not fit to caps with streaming-format=avc.
We use h264parse to change streaming-format byte-stream (before) to avc (afterwards).
Is there a more intelligent way needed after h264parse instead of just forcing caps to solve link problem?

Another thing I am currently unsure: When we dynamically add h264parse, is there some synchronization to frame data needed, so we start exactly at the beginning of a GOP?
But we are already on compressed side, so is it relevant at all?

Many thanks!

Best regards,

Marie

-----Ursprüngliche Nachricht-----
Von: gstreamer-devel [mailto:gstreamer-devel-bounces at lists.freedesktop.org] Im Auftrag von Nicolas Dufresne
Gesendet: Mittwoch, 12. Dezember 2018 18:39
An: Discussion of the development of and with GStreamer <gstreamer-devel at lists.freedesktop.org>
Betreff: Re: "broken/invalid nal" with h264parse after v4l2h264enc on i.MX6

Le mercredi 12 décembre 2018 à 17:12 +0000, Maurer, Marie a écrit :
> Hello,
>  
> environment is GStreamer 1.14.2 on Linux with i.MX6 (most of it latest 
> mainlined versions)

Please, try again with 1.14.4, as there is some fixes in the 1.14 stable branch. And if you can, complain to Yocto people who seem not to stay up-to-date with stable.

>  
> I see a lot messages like the following:
>  
> WARN   h264parse gsth264parse.c:1237:gst_h264_parse_handle_frame:<RecorderH264Parser> broken/invalid nal Type: 1 Slice, Size: 81703 will be dropped
>  
> Size is changing, but always around between 50000 and 80000.
>  
> I think the relevant part of my pipeline is a v4l2h264enc and after some queues and tees a h264parse.
>  
> Is it correct that somehow the parser does not understand the data which the v4l2h264enc is generating?
> Or the data which the encoder is generating gets sometimes somehow corrupted till it is received by h264parse?

Hard to say, though it's better to update first, and see if any of the upstream bugfixes improves the situation.

>  
> Any idea how it can be solved?

You would have to share the pipeline you are using, the settings and all. Ideally if you can reproduce in gst-launch-1.0 form, then I could try reproduce locally.

>  
> Best regards,
>  
> Marie
>  
> _______________________________________________
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> gstreamer-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel

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