a possible bug in gstreamer?

[kendell clark]

hi all

I'm a new user to this list, having just signed up about a month ago. My
name is Kendell clark, and I've been a gnu linux user since august of
2011. I am visually impaired, and work with the vinux project, which is
an accessible linux distro for those who need assistive technologies,
such as the orca screen reader, on board on screen keyboard, and
magnification, as well as other programs. I am also not a programmer,
yet. However, I use linux every day and want to help improve some of the
best code I've ever had the pleasure of using, and that is gstreamer.
I'd like to report what I think might, maybe, be a bug or two in
gstreamer. First, in opening the matroska video file format (.mkv    ).
In totem, which is actually called videos now, attempting to open a mkv
file results in the following error.

"an error occurred internal data stream error."

This is, I believe a gstreamer error, because although other video
players which use gstreamer such as parole, will open these files, it
brings the system to it's knees with artifacts and general lag. If it
helps, which I'm not sure if it does or not, these are videos downloaded
from youtube with youtube-dl and converted with ffmpeg automatically.
I'm using a dell inspiron n7010 with a quad core processor, and 6 gb of
ram, so I'm pretty sure but not positive it's not a hardware issue.
Second, there's a problem in a program for converting audio called sound
converter. It uses gstreamer to convert audio files from one format to
another and strip the audio out of video files. This is a hard bug to
track down, but it's simple to reproduce. Open a folder with lots of
files, or lots of folders with lots of files, in other words, lots of
subdirectories with lots of audio or video files. The application will
be slow to parse the file list, but will eventually complete. However,
after pressing the convert button it will simply stop. It acts as if it
is converting but isn't actually doing anything. The only reason I think
these might be gstreamer bugs is because these bugs started happening
with the last release of gstreamer 1.x, version 1.12.0-1. If it helps,
I'm running antergos 2017.06, completely up to date. I'd like to help
diagnose this problem and also help fix it. If it's not a gstreamer
problem I apologize, but would appreciate pointers to these project's
respective bug reporting pages if it's not a gstreamer error. Lastly,
opening these mkv files in vlc media player works fine, but as far as I
know it doesn't use gstreamer, which is further evidence of a possible
gstreamer bug. Before I go, I have the good, bad and ugly plugin sets
installed, and will gladly help debug, send debug logs, whatever is
needed as long as it doesn't require writing code. I can't do taht yet,
but I'm trying to learn.


Appreciate any help.

Thanks

Kendell Clark


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[Mark Howell]

On 06/07/2017 11:25 AM, kendell clark wrote:

> hi all
>
> I'm a new user to this list, having just signed up about a month ago.
> My name is Kendell clark, and I've been a gnu linux user since august
> of 2011. I am visually impaired, and work with the vinux project,
> which is an accessible linux distro for those who need assistive
> technologies, such as the orca screen reader, on board on screen
> keyboard, and magnification, as well as other programs. I am also not
> a programmer, yet. However, I use linux every day and want to help
> improve some of the best code I've ever had the pleasure of using, and
> that is gstreamer.

Kendell, welcome. I didn't want you to go unanswered so I'm offering
some comments below that I hope will a) help you fix your problems and
b) enable your increased participation and contribution here and in
other open source projects with a bajillion moving parts and priorities.

> I'd like to report what I think might, maybe, be a bug or two in
> gstreamer. First, in opening the matroska video file format (.mkv    
> ). In totem, which is actually called videos now, attempting to open a
> mkv file results in the following error.
>
> "an error occurred internal data stream error."
>

[snipped some narrative about possible bugs]

It's entirely possible you have found one or more gstreamer bugs. This
is the place where people who know how to work those bugs can be found.
Those folks are busy adding features, curing ills, and moving the thing
forward and have many people and issues competing for their attention.
To maximize the likelihood of getting their attention, do whatever you
can to put each issue on a silver platter. That means reduce how much
work and research they have to do to reproduce the problem, and reduce
the search space or variables for solving it. Some suggestions:

* First go see if your issue looks like another one already in bugzilla
(https://gstreamer.freedesktop.org/bugs/). Try to avoid filing a
duplicate... instead add useful comments or test cases to the existing
bug. Often it's not obvious that a bug is a duplicate, and the
responsible devs may figure it out and mark it as a duplicate as they go.

* Read other bugs for examples of what to report and how.

* If your issue is not a duplicate, file a bug, one for each issue, as
well as you can separate them.

* In each bug report, include a test case that is as simple, direct, and
self-contained as possible (like a gst-launch commandline and a link to
a publicly available media file, or a gst-launch test case that can run
entirely from test "equipment" inside the gstreamer borders like
videotestsrc).

* Be real specific about versions (try gst-launch-1.0 --version, or if
you are building from source... what tag or commit? did it come from
your Linux distribution's repo?) Folks here will be more motivated to
cure a bug on the current master or release branch than an older
release. Also it may be worthwhile to know what kernel you are running
(uname -a), what version(s) of other relevant libraries you are running.
Architecture? ( x86_64, x86, etc)

* If you can, try it on another system or with a different version of
gstreamer. Does it do the same on Windows, or a Mac, or on the release
from the Ubuntu repo? Does 1.8.x work fine with your file but 1.12.x
doesn't?

* After you file the bug, watch its activity and be ready to respond to
requests for logs, test cases, library versions,
try-this-instead-of-that, etc.

Cheers,

Mark.

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