Is it a good way to separate pipelines in order to dynamically change properties?

[Nicolas Dufresne]

Le lundi 07 août 2023 à 20:07 +0900, geysee via gstreamer-devel a écrit :
> Hi,
> 
> Mr. Nicolas.
> 
> 
> I'm Kamiya.
> 
> 
> I'm trying to combine multiple files with the splitmuxsrc signal
> "format_location" you advised.
> 
> I haven't tried concat element yet. I thought that splitmuxsrc would be more
> suitable because of the large number of files.
> 
> 
> It succeeded when the return value of GStrv* type was initialized as an
> array.(code below)
> 
> 
> -----------------------------
> 
> static GStrv* formatLocationHandler(GstElement *splitmux, gpointer udata)
> 
> {
> 
>     gchar *locations[4];
> 
> 
>     locations[0] = g_strdup("C:/Rec/2023/07/26/1808_28911.mp4");
> 
>     locations[1] = g_strdup("C:/Rec/2023/07/26/1808_38919.mp4");
> 
>     locations[2] = g_strdup("C:/Rec/2023/07/26/1808_47902.mp4");
> 
>     locations[3] = nullptr;
> 
> 
>     GStrv *ret  = (GStrv*)g_new0(GStrv, 1);
> 
>     std::memcpy(ret, &locations, sizeof(locations));

You have 1 pointer allocated, but memcopy 4, this is going to overflow.

> 
> 
> 
>     return ret;
> 
> }
> 
> -----------------------------
> 
> 
> On the other hand, if the return value was dynamically allocated, it will be
> crashed after exiting formatLocationHandler.(code below)
> 
> 
> -----------------------------
> 
> static GStrv* formatLocationHandler(GstElement *splitmux, gpointer udata)
> 
> {
> 
>     gchar **locations = (gchar**)g_new0(gchar*, 4);
> 
> 
>     locations[0] = g_strdup("C:/Rec/2023/07/26/1808_28911.mp4");
> 
>     locations[1] = g_strdup("C:/Rec/2023/07/26/1808_38919.mp4");
> 
>     locations[2] = g_strdup("C:/Rec/2023/07/26/1808_47902.mp4");
> 
>     locations[3] = nullptr;
> 
> 
>     GStrv *ret  = (GStrv*)g_new0(GStrv, 1);
> 
>     std::memcpy(ret, &locations, sizeof(locations));

Same bug, it just worked by accident previously.

> 
> 
> 
>     return ret;
> 
> }
> 
> -----------------------------
> 
> 
> Could you tell me how to dynamically allocate the file list in
> formatLocationHandler ?
> 
> I am very embarrassed that it may be a basic problem with C language or GLib,
> but I have been unable to solve it for a long time, so I would appreciate your
> help.
> 
> 
> Best regards,
> 
> Kamiya.
> 
> 
> 
> SHIGEHARU KAMIYA/TOA wrote on 2023/08/03 12:04:11:
> 
> > 
> > Hi,
> 
> > Mr. Nicolas.
> 
> > 
> > Thank you for your reply.
> 
> > Your way looks nice!
> 
> > 
> > I am trying it now.
> 
> > I will let you know the results later.
> 
> > 
> > Thank you.
> 
> > Kamiya.
> 
> > 
> > "gstreamer-devel" <gstreamer-devel-bounces at lists.freedesktop.org>
> > wrote on 2023/08/03 07:09:52:
> 
> > > 
> > > Hi,
> 
> > > Le mar. 1 août 2023, 03 h 15, geysee via gstreamer-devel <
> > > gstreamer-devel at lists.freedesktop.org> a écrit :
> 
> > > > Hello
> > > > I am Kamiya.
> > > >
> > > > I have a question.
> > > >
> > > > Is it a good way to separate pipelines in order to dynamically change
> > > > properties
> > > > that cannot be changed in the PLAYING state, such as the location
> property
> > > > in filesrc?
> 
> > > 
> > > It can be a good method. But from what you described below, you may get
> > > easier results with concat element instead. splitmuxsrc should work, there
> > > is a signal to query the filename from your app instead of using the glob.
> 
> > > 
> > > >
> > > > I'm sorry for the long post, but the background of the question is as
> > > > follows.
> > > >
> > > >
> > > > 
> > > 
> > ----------------------------------------------------------------------------
> -----------------------------------------------------
> > > > I'm making a system that records video from a network camera while
> > > > dividing it into files.
> > > > If the file is split at 10 minute intervals, the file path will be as
> > > > follows.
> > > >
> > > > C:/Rec/2023/07/31/1330_00000.mp4
> > > > C:/Rec/2023/07/31/1340_00000.mp4
> > > > C:/Rec/2023/07/31/1350_00000.mp4
> > > >
> > > > With gstreamer C++ coding, I am trying to export as a single file by
> > > > specifying the date and time range from the divided recording files.
> > > >
> > > > If the date and time range is in one file, like 13:32 - 13:34, then the
> > > > pipeline below has been successful. (Properties are omitted)
> > > >
> > > > pileline : filesrc ! qtdemux ! h265parse ! queue ! qtmux ! filesink
> > > >
> > > > On the other hand, if the date and time range is split into multiple
> > > > files, like 7/31 20:00 - 8/1 10:00, this pipeline fails.
> > > >
> > > > First, I tried multifilesrc and splitmuxsrc, but the location property
> is
> > > > a glob pattern, it didn't fit the file path of date and time.
> > > > Next, I tried updating the location property of filesrc sequentially,
> but
> > > > I couldn't change the location when this state is PLAYING.
> > > >
> > > > So now I'm trying to divide the pipeline into two as follows.
> > > >
> > > > pipeline1 : filesrc ! qtdemux ! h265parse ! appsink
> > > > pipeline2 : appsrc ! queue ! qtmux ! filesink
> > > >
> > > > When pipeline1 reaches the end of stream, I change the state of
> pipeline1
> > > > to Ready.
> > > > Next I change the location of filesrc. Finaly I change state to PLAYING
> > > > again.
> > > > The State of pipeline2 is not changed.
> > > >
> > > > However this way has not been successful yet. There are more problems
> than
> > > > single pipeline.
> > > >
> > > > Currently looking into the following issues:
> > > > If there was single pipeline it was processed at high speed, but if the
> > > > pipeline is divided, the processing time will be as per the timestamp.
> > > >
> > > > Is it a good way to split the pipeline like this?
> > > > I would appreciate if you give me some advice.
> > > >
> > > > 
> > > 
> > ----------------------------------------------------------------------------
> -----------------------------------------------------
> > > >
> > > > Best regards,
> > > > Kamiya.
> 

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