two problems with latest matroska mux/demux

[Tim Müller]

On Fri, 2015-07-24 at 15:51 -0600, Glen Diener wrote:

Hi,

> I have run into two problems with the matroska plugins in
> plugins-good, working with the latest development build, as of July
> 24, 2015.
> 
> 
> First, I can't get matroskamux to write track tags unless I set the
> 'streamable' property to true.  As a simple demo:
> 
> $ gst-launch-1.0 -e videotestsrc ! taginject tags=comment=hello !
> matroskamux ! filesink location=x.mkv
> 
> After control-c, running "mkvinfo x.mkv"  indicates the 'comment' tag
> is not set. Rerunning with streamable=true:
> 
> $ gst-launch-1.0 -e videotestsrc ! taginject tags=title=hello !
> matroskamux streamable=true ! filesink location=x.mkv
> 
> ...and mkvinfo verifies that the tag is now set.  I can see from the
> source code (matroskamux.c, line 2573) that this is intentional
> behavior.  Can someone suggest why this is so?  I modified
> matroskamux.c to delete this requirement: this  fixed it for me, and
> nothing has blown up so far.
> 
> 
> Second, and more vexing, I can not get gstreamer to report track tags
> at all. I know they are in there (mkvinfo tells me so), but I can't
> extract them in my own application code and, it seems, neither can
> gst-launch. For example:
> 
> $ gst-launch-1.0 -e videotestsrc ! taginject tags=comment=hello !
> matroskamux streamable=true ! filesink location=x.mkv
> 
> mvkinfo verifies that the tag is set. But the following only reports
> the implicit tags:
> 
> $ gst-launch-1.0 -t filesrc location=./x.mkv ! matroskademux ! fakesink
> 
> Setting pipeline to PAUSED ...
> Pipeline is PREROLLING ...
> FOUND TAG      : found by element "fakesink0".
> container format: Matroska
> FOUND TAG      : found by element "fakesink0".
>      video codec: Uncompressed planar YUV 4:4:4
> Pipeline is PREROLLED ...
> Setting pipeline to PLAYING ...
> 
> Am I missing something, or is this just broken?
> mer-devel

Could you file bugs for these in bugzilla please
(http://gstreamer.freedesktop.org/bugs/) and attach your patch there
too? Thanks!

I'm sure some stream tags are picked up, because they contain things
like audio and subtitle language, and I'm sure someone would've noticed
if those are no longer working..

 Cheers
  -Tim

-- 
Tim Müller, Centricular Ltd - http://www.centricular.com