avdec_h264 is not copying metadata to the outputbuffer

[parithi]

I have implemented a new GstMeta with tag "video". It is populated in h264parse plugin and sent to downstream along with the output buffer. I am expecting all downstream elements should propagate this meta data along with output buffer. But if I run the following pipeline

gst-launch-1.0 filesrc location=input.ts ! tsdemux ! h264parse ! 'video/x-h264, stream-format=byte-stream' ! avdec_h264 ! x264enc ! mpegtsmux ! filesink location=out.ts

I am getting following error.

(gst-launch-1.0:22191): GStreamer-CRITICAL **: gst_buffer_add_meta: assertion 'gst_buffer_is_writable (buffer)' failed
Caught SIGSEGV.

From my analysis, I found that refcount of avdec_h264 is always 2. So the transform function is failed to append meta data to the outputbuffer.

Please let me if you have any suggestion/solution for this issue?

[Tim Müller]

On Wed, 2016-11-23 at 04:43 -0800, parithi wrote:

Hi,

> But if I run the following pipeline
>
> gst-launch-1.0 filesrc location=input.ts ! tsdemux ! h264parse !
> 'video/x-h264, stream-format=byte-stream' ! avdec_h264 ! x264enc !
> mpegtsmux
> ! filesink location=out.ts
>
> I am getting following error.
>
> (gst-launch-1.0:22191): GStreamer-CRITICAL **: gst_buffer_add_meta:
> assertion 'gst_buffer_is_writable (buffer)' failed
> Caught SIGSEGV.
>
> From my analysis, I found that refcount of avdec_h264 is always 2. So
> the transform function is failed to append meta data to the
> outputbuffer.
>
> Please let me if you have any suggestion/solution for this issue?

Please could you file a bug about this in bugzilla (against gst-libav)?

https://gstreamer.freedesktop.org/bugs/
--
Tim Müller, Centricular Ltd - http://www.centricular.com
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[sudipj]

I am using 1.10 version and don't get this issue.

Regards,

Sudip

On 23 November 2016 at 18:42, Tim Müller [via GStreamer-devel] <[hidden email]> wrote:

On Wed, 2016-11-23 at 04:43 -0800, parithi wrote:

Hi,

> But if I run the following pipeline
>
> gst-launch-1.0 filesrc location=input.ts ! tsdemux ! h264parse !
> 'video/x-h264, stream-format=byte-stream' ! avdec_h264 ! x264enc !
> mpegtsmux
> ! filesink location=out.ts
>
> I am getting following error.
>
> (gst-launch-1.0:22191): GStreamer-CRITICAL **: gst_buffer_add_meta:
> assertion 'gst_buffer_is_writable (buffer)' failed
> Caught SIGSEGV.
>
> From my analysis, I found that refcount of avdec_h264 is always 2. So
> the transform function is failed to append meta data to the
> outputbuffer.
>
> Please let me if you have any suggestion/solution for this issue?

Please could you file a bug about this in bugzilla (against gst-libav)?

https://gstreamer.freedesktop.org/bugs/
--
Tim Müller, Centricular Ltd - http://www.centricular.com
_______________________________________________
gstreamer-devel mailing list
[hidden email]
https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel

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[parithi]

Tim Müller,

I filed a bug : https://bugzilla.gnome.org/show_bug.cgi?id=774983

Sudip,

I am using 1.10.0. Are you using the same version?

Regards,
Parithi

[sudipj]

Parithi,

Its 1.10.0.

sudipjai@dell-ubuntu-laptop:~/gst/head/gst-libav$ gst-launch-1.0 --version
gst-launch-1.0 version 1.10.0
GStreamer 1.10.0
Unknown package origin

sudipjai@dell-ubuntu-laptop:~/gst/head/gst-libav$ gst-launch-1.0 filesrc location= ~/Streams/_TS/h264.ts ! tsdemux ! h264parse ! 'video/x-h264, stream-format=byte-stream' ! avdec_h264 ! x264enc ! mpegtsmux ! filesink location=out.ts Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
Redistribute latency...
Redistribute latency...
Redistribute latency...
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
Got EOS from element "pipeline0".
Execution ended after 0:00:11.894069396
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...
sudipjai@dell-ubuntu-laptop:~/gst/head/gst-libav$

Regards,

Sudip

On 24 November 2016 at 12:07, parithi [via GStreamer-devel] <[hidden email]> wrote:

Tim Müller,

I filed a bug : https://bugzilla.gnome.org/show_bug.cgi?id=774983

Sudip,

I am using 1.10.0. Are you using the same version?

Regards,
Parithi

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[parithi]

Sudip,

Even I don't have any problem running this pipeline without meta data(with tag "video"). But problem arises when I add meta data with ouput buffer of h264_parse. The decoder element should copy this meta data on it's output buffer and pass it to downstream element.

avdec_h264 is receiving all meta data. I've checked this. Problem arises when it tries to add the meta data to its output buffer. The pipeline crashes at gst_buffer_add_meta(), since the buffer passed from avdec_h264 is not in writable mode.
call stack:
--------------------------------
#2 gst_buffer_add_meta
#3 gst_buffer_add_h264_meta
#4 gst_h264_meta_transform
#5 foreach_metadata
#6 gst_buffer_foreach_meta
#7 gst_video_decoder_finish_frame
#8 gst_ffmpegviddec_frame
----------------------------------
If the meta tag is "video" the frame work will do the copying, otherwise we have to retrieve it from input buffer and append it to the outut buffer.
I tried both ways, but the behaviour is same.  

Please let me know if you have any suggestion to resolve this issue.

Regards,
Parithi

[sudipj]

I faced this issue earlier, the only difference being that I added video meta-data into hardware decoder plugin (vpudec) instead of h264parse.  I don't have the proper clue of the real issue, having a consumer of the output buffer downstream avoids it.  Here are some results that could help

.. h264parse ! vpudec ! videoconvert ! fakesink - error

.. h264parse ! vpudec ! videoconvert ! video/-raw, format =I420 ! fakesink  -the output of vpudec is NV12 format. Force video convert to avoid bypass mode - No error

.. h264patrse ! vpudec ! videorga ! fakesink - No error , videorga is hardware post process element, checks for the video meta data and copies to the output buffer, so I don't get the issue and is my default use case. I didn't investigated further.

You could give a similar try to your pipeline, though I am not sure as the the meta data is added in h264parse element. Or just try this if the same error comes
gst-launch-1.0 filesrc location=input.ts ! tsdemux ! h264parse ! fakesink

Then you could keep adding element..

Regards,

Sudip

On 24 November 2016 at 14:38, parithi [via GStreamer-devel] <[hidden email]> wrote:

Sudip,

Even I don't have any problem running this pipeline without meta data(with tag "video"). But problem arises when I add meta data with ouput buffer of h264_parse. The decoder element should copy this meta data on it's output buffer and pass it to downstream element.

avdec_h264 is receiving all meta data. I've checked this. Problem arises when it tries to add the meta data to its output buffer. The pipeline crashes at gst_buffer_add_meta(), since the buffer passed from avdec_h264 is not in writable mode.
call stack:
--------------------------------
#2 gst_buffer_add_meta
#3 gst_buffer_add_h264_meta
#4 gst_h264_meta_transform
#5 foreach_metadata
#6 gst_buffer_foreach_meta
#7 gst_video_decoder_finish_frame
#8 gst_ffmpegviddec_frame
----------------------------------
If the meta tag is "video" the frame work will do the copying, otherwise we have to retrieve it from input buffer and append it to the outut buffer.
I tried both ways, but the behaviour is same.  

Please let me know if you have any suggestion to resolve this issue.

Regards,
Parithi

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[parithi]

Sudip,

Thanks for your input.

gst-launch-1.0 filesrc location=input.ts ! tsdemux ! h264parse ! fakesink - There is no issue with this pipeline.

avdec_h264 is the only software plugin available for h264 decoding. If I add this in to the pipeline, then the issue arises.

Any I'll try some other pipeline configuration and update you.

Regards,
Parithi