[Bug 707586] New: Application Development Manual: add gst-launch crash course before diving into code

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=707586
  GStreamer | documentation | git

           Summary: Application Development Manual: add gst-launch crash
                    course before diving into code
    Classification: Platform
           Product: GStreamer
           Version: git
        OS/Version: Linux
            Status: NEW
          Severity: enhancement
          Priority: Normal
         Component: documentation
        AssignedTo: gstreamer-bugs at lists.freedesktop.org
        ReportedBy: t.i.m at zen.co.uk
         QAContact: gstreamer-bugs at lists.freedesktop.org
     GNOME version: ---


Ian Davidson suggested this:

On the GStreamer web site it says “Application Development Manual (Read this
first) ” - so that would seem to be the place to start if you want to learn
about Gstreamer.

Very early in the document (section 2.1), it says that “The programmer can use
an extensive set of powerful tools to create media pipelines without writing a
single line of code. ” That is good to know and is brought about by the library
of 'Plug-ins'.

But – then as you continue to read the manual, you are thrown heavily into
programming. Straight away.

Might I suggest that very early on you have mention of gst-launch – since,
using that you can do things without having to write a single line of coding.
However, the chapter on gst-launch itself is not an easy-to-read chapter: It
starts with a 'simple commandline' and then shows a more complex one – but
without any explanation. If we take the first example

gst-launch filesrc location=hello.mp3 ! mad ! audioresample ! osssink

you could then describe what is happening. e.g.:

gst-launch is a program which enables the user to construct pipelines using
command-line parameters.
Filesrc is an element (or a plugin) – in this case it will read data from a
file and needs to know the name of the file to open. It will output the data so
as to be the source for the next element in the pipe-line.
The “!” symbol separates the first element from the next.
mad is the next element in the pipe-line: It will decode mp3 data. It picks up
the source provided by the previous element and then outputs the decoded data
for the next element in the pipe-line.
Once again, a “!” symbol separates the elements.
audioresample resamples the Audio. (I don’t know why this is a benefit – it
could be explained)
Another “!”
osssink takes the audio signal and sends it to an output device which supports
(or is supported by) OSS.

The second example could then be similarly explained – which would be a useful
exercise since the single vob file is being demuxed with part of the data going
one way and the rest another. A reference, at this point to the Overview of
available plug-ins would be beneficial. Perhaps an example where more options
need to be specified could also be explained.

Then you can say that, if you need to build this into an application, you can
do the same stuff with code and if you need to do something which is not
currently supported, you can write your own plug-in – so read on...

I hope this is useful

-- 
Configure bugmail: https://bugzilla.gnome.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.
You are the assignee for the bug.