Linux/AM5728: convert g-streamer pipeline to c code

Avinash Gowtham

Part Number: AM5728

Tool/software: Linux

Hi,

I'm using a G-streamer pipeline to display the mp4 file in my location.

pipeline is : gst-launch-1.0 filesrc location=/home/m/TearOfSteel-AV-Short-720x406.mp4 ! decodebin name=dec ! videoconvert ! autovideosink dec. ! audioconvert ! audioresample ! alsasink

Normally it is working, but my problem is in converting that pipeline to a C code

I want to convert the below decoders into c code

decodebin name=dec

autovideosink dec.

suggest me.

Regards,

GAG.

over 6 years ago

0 Margarita Gashova over 6 years ago

TI__Guru* 80190 points

Hello,

Please refer the below guides about pads:
gstreamer.freedesktop.org/.../pads.html
gstreamer.freedesktop.org/.../media-formats-and-pad-capabilities.html

Here is an example:
gist.github.com/.../276365488873665d81a3f1230afa2d6f
Refer this function:
static void cb_new_pad (GstElement *element, GstPad *pad, gpointer data)
{
gchar *name;
GstElement *other = data;

name = gst_pad_get_name (pad);
g_print ("A new pad %s was created for %s\n", name, gst_element_get_name(element));
g_free (name);

g_print ("element %s will be linked to %s\n",
gst_element_get_name(element),
gst_element_get_name(other));
gst_element_link(element, other);
}
....

g_signal_connect (dec, "pad-added", G_CALLBACK (cb_new_pad), conv);

Hope this helps.

BR
Margarita

0 Margarita Gashova over 6 years ago in reply to Margarita Gashova

TI__Guru* 80190 points

Hello,

Please refer the below guide:
software-dl.ti.com/.../Foundational_Components_Multimedia.html
You could find gst pipelines about decode where ducati is used and vpe.
I would recommend you to try these pipelines.

You could try this also:

#include <gst/gst.h>

#include <stdio.h>

int main(int argc, char *argv[])

{

GstElement *pipeline;

GstBus *bus;

GstMessage *msg;

const gchar *nano_str;

guint major, minor, micro, nano;

/* Initialize GStreamer */

gst_init (&argc, &argv);

gst_version (&major, &minor, &micro, &nano);

printf ("GStreamer Version: %d.%d.%d\n",major, minor, micro);

/* Build the pipeline */

pipeline = gst_parse_launch(" playbin uri=file:////home/m/TearOfSteel-AV-Short-720x406.mp4 video-sink=waylandsink audio-sink=alsasink", NULL);

/* Start playing */

gst_element_set_state (pipeline, GST_STATE_PLAYING);

/* Wait until error or EOS */

bus = gst_element_get_bus (pipeline);

msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS);

/* Free resources */

if (msg != NULL)

gst_message_unref (msg);

gst_object_unref (bus);

gst_element_set_state (pipeline, GST_STATE_NULL);

gst_object_unref (pipeline);

return 0;

}

gstreamer.freedesktop.org/.../gstreamer-GstParse.html

BR
Margarita

0 Avinash Gowtham over 6 years ago in reply to Margarita Gashova

Prodigy 225 points

Hi Margarita,

Thanks for the reply. It is helpful to me.

One more query is, I'm having a g-streamer pipeline in which i want to replace the decoder with other decoder which is useful in playback the video.

My pipeline is :
gst-launch-1.0 filesrc location=/home/g/TearOfSteel-AV-Short-1024x1024.mp4 ! decodebin ! videoconvert ! autovideosink

I want to replace "decodebin" with other decoder, which is helpful in displaying the Mp4 video.

suggest me.

Regards,
GAG.

0 Margarita Gashova over 6 years ago in reply to Avinash Gowtham

TI__Guru* 80190 points

Hello,

Here you could find what decodebin do gstreamer.freedesktop.org/.../gst-plugins-base-plugins-decodebin.html

These are TI decoders :

ducatih264dec
ducatimpeg4dec
ducatimpeg2dec
ducativc1dec
ducatijpegdec

I would recommend you to use ducati and VPE if possible because if you use software decoder and videoconvert the CPU will be high and frame drop could be observed.

One of the option is to use playbin(gstreamer.freedesktop.org/.../gst-plugins-base-plugins-playbin.html).
gst-launch-1.0 playbin uri=file:///<path_to_file> video-sink=kmssink audio-sink=alsasink
This will link all the elements and it is easy to be use in c application.

The other option is to use pipeline like this:
gst-launch-1.0 -v filesrc location=example_h264.mp4 ! qtdemux ! h264parse ! ducatih264dec ! vpe ! 'video/x-raw, format=(string)NV12, width=(int)720, height=(int)480' ! kmssink

Please change qtdemux if there is a need. You could check the available demuxers by using this command:
gst-inspect-1.0 | grep "demux"

As you could see in the above example kmssink is used as displaysink so please stop weston.
/etc/init.d/weston stop
If you are using waylandsink please do no stop weston.

In the above example there is no audio branch only video but you could add it.
That is why you must use a demuxer in the pipeline. Demuxer element has one input(sink) and N-1 src pad(outputs) one for each elementary stream contained in the container format(video, audio, subtitle ).
You could run gst-inspect-1.0 qtdemux

Here is example for demuxer
gst-launch-1.0 -v filesrc location=<file> ! qtdemux name=demux demux.audio_0 ! queue ! <audioparser> ! <audiodecoder> ! alsasink demux.video_0 ! queue ! <videoparse> ! <videodecoder> ! waylandsink

Hope this helps.

BR
Margarita

0 Margarita Gashova over 6 years ago in reply to Margarita Gashova

TI__Guru* 80190 points

Hello,

Thank you! If you have new question/issue please open a new thread.
Please take a look into this
gstreamer.freedesktop.org/.../playbin-usage.html
there is an example of playbin in c application.

BR
Margarita

Processors

Processors forum

Linux/AM5728: convert g-streamer pipeline to c code