AW: Re: Play a file while downloading it (appending new data to it)

[Bernhard Graaf]

Hi Stefan,

Very interesting! I'm working also on that.
Do you have any example c-code for a solution?

BG
Bernhard
Gesendet mit BlackBerry von Vodafone

-----Original Message-----
From: Stefan Sauer <ensonic at hora-obscura.de>
Sender: gstreamer-devel-bounces+bernhard.graaf=gmx.de at lists.freedesktop.org
Date: Fri, 14 Oct 2011 09:26:28 
To: <gstreamer-devel at lists.freedesktop.org>
Reply-To: Discussion of the development of and with GStreamer
	<gstreamer-devel at lists.freedesktop.org>
Subject: Re: Play a file while downloading it (appending new data to it)

On 10/13/2011 09:33 PM, Florin Curelaru wrote:
>    Hi guys,
>
>  I'm trying to find a simple solution for playing a local file that is
> updated from time to time (by appending new data).
This has been discussed a few times before on the list. It won't work
out of the box with the current filesrc element.
The file-src element would need to be aware that the size is changing
and e.g. on every read, check the size and if changed send a new
duration message downstream.

Stefan
>  The problem appears when using standard source elements (let's say filesrc)
> as the duration of the file is not updated after having finished the first
> preroll process of the pipeline. That will cause a premature generation of
> an EOS message when the current position reaches the initial size of the
> file, even though the file was update many times meanwhile. There are some
> exceptions for some pipeline configurations, especially when no seek was
> requested and the file continues playing till the end of the updated file,
> but I'm not interested in them as the duration doesn't follow accurately the
> updates of the file.
>
>  I tried first time to use the gnfilesource as source element (from gnolin
> library) which allows to set a total duration as desired. It works very well
> with some codecs, but crashes on hardware for any mp3 file when using in
> conjunction with the nv_omx_mp3dec.
>  By using gst-launch the pipeline looks similar to:
>
>  gst-launch gnlfilesource location=path_to_mp3_file start=0
> duration=20000000000 ! mp3parse ! nv_omx_mp3dec ! alsasink
>
>  and  a segmentation fault is encountered after a seek event rposted by the
> gnl object. When using filescr instead of gnlfilesource the song is played,
> but till the end of initial size.
>
>
>  I tried also to post a message_new_duration (with a specific value for
> duration) in order to update the pipeline internal variable for duration,
> but on the pipeline's bus appears the message (GST_MESSAGE_DURATION) with
> the initial duration of the file.
>
>
>  So, I'm looking for a simple solution to play and seek into a file that is
> downloaded on the fly. I think that an approach based on a source plugin is
> not an easy task as long as nv_omx_mp3dec causes unexpected crashes in
> ordinary situations.
>
> Thank you in advance,
> Florin
>
> --
> View this message in context: http://gstreamer-devel.966125.n4.nabble.com/Play-a-file-while-downloading-it-appending-new-data-to-it-tp3902651p3902651.html
> Sent from the GStreamer-devel mailing list archive at Nabble.com.
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