Can not get right data from appsink in python

[Yawei Wang]

I use python to get data from appsink. My code is like below:
```
import gi
gi.require_version('Gst', '1.0')
gi.require_version('GstApp', '1.0')
from gi.repository import GObject, Gst, GstApp

GObject.threads_init()
Gst.init(None)


class Example:
    def __init__(self):
        self.mainloop = GObject.MainLoop()
        self.pipeline = Gst.Pipeline()
        self.bus = self.pipeline.get_bus()
        self.bus.add_signal_watch()
        self.bus.connect('message::eos', self.on_eos)
        self.bus.connect('message::error', self.on_error)

        # Create elements
        self.src = Gst.ElementFactory.make('v4l2src', None)
        self.encoder = Gst.ElementFactory.make('x264enc', None)
        self.parse = Gst.ElementFactory.make('h264parse', None)
        self.mux = Gst.ElementFactory.make('flvmux', None)
        self.sink = Gst.ElementFactory.make('appsink', None)

        # Add elements to pipeline
        self.pipeline.add(self.src)
        self.pipeline.add(self.encoder)
        self.pipeline.add(self.parse)
        self.pipeline.add(self.mux)
        self.pipeline.add(self.sink)

        # Set properties
        self.src.set_property('device', "/dev/video0")

        # Link elements
        self.src.link(self.encoder)
        self.encoder.link(self.parse)
        self.parse.link(self.mux)
        self.mux.link(self.sink)

    def run(self):
        self.pipeline.set_state(Gst.State.PLAYING)
        # self.mainloop.run()
        appsink_sample = GstApp.AppSink.pull_sample(self.sink)
        while True:
            buff = appsink_sample.get_buffer()
            size, offset, maxsize = buff.get_sizes()
            frame_data = buff.extract_dup(offset, size)
            print(frame_data)

    def kill(self):
        self.pipeline.set_state(Gst.State.NULL)
        self.mainloop.quit()

    def on_eos(self, bus, msg):
        print('on_eos()')
        self.kill()

    def on_error(self, bus, msg):
        print('on_error():', msg.parse_error())
        self.kill()


example = Example()
example.run()
```

But I got the same data like "FLV\0x01\0x01". Someone could answer the
question?



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[Matthew Waters]

On 12/01/18 12:56, Yawei Wang wrote:

> I use python to get data from appsink. My code is like below:
> ```
> import gi
> gi.require_version('Gst', '1.0')
> gi.require_version('GstApp', '1.0')
> from gi.repository import GObject, Gst, GstApp
>
> GObject.threads_init()
> Gst.init(None)
>
>
> class Example:
>     def __init__(self):
>         self.mainloop = GObject.MainLoop()
>         self.pipeline = Gst.Pipeline()
>         self.bus = self.pipeline.get_bus()
>         self.bus.add_signal_watch()
>         self.bus.connect('message::eos', self.on_eos)
>         self.bus.connect('message::error', self.on_error)
>
>         # Create elements
>         self.src = Gst.ElementFactory.make('v4l2src', None)
>         self.encoder = Gst.ElementFactory.make('x264enc', None)
>         self.parse = Gst.ElementFactory.make('h264parse', None)
>         self.mux = Gst.ElementFactory.make('flvmux', None)
>         self.sink = Gst.ElementFactory.make('appsink', None)
>
>         # Add elements to pipeline
>         self.pipeline.add(self.src)
>         self.pipeline.add(self.encoder)
>         self.pipeline.add(self.parse)
>         self.pipeline.add(self.mux)
>         self.pipeline.add(self.sink)
>
>         # Set properties
>         self.src.set_property('device', "/dev/video0")
>
>         # Link elements
>         self.src.link(self.encoder)
>         self.encoder.link(self.parse)
>         self.parse.link(self.mux)
>         self.mux.link(self.sink)
>
>     def run(self):
>         self.pipeline.set_state(Gst.State.PLAYING)
>         # self.mainloop.run()
>         appsink_sample = GstApp.AppSink.pull_sample(self.sink)

This needs to be in the while loop below.

What the code currently says is:
1. Pull one sample
2. While true, get the buffer from the sample (this will always return
the same buffer).


What you want is to pull_sample() inside the while loop

>         while True:
>             buff = appsink_sample.get_buffer()
>             size, offset, maxsize = buff.get_sizes()
>             frame_data = buff.extract_dup(offset, size)
>             print(frame_data)
>
>     def kill(self):
>         self.pipeline.set_state(Gst.State.NULL)
>         self.mainloop.quit()
>
>     def on_eos(self, bus, msg):
>         print('on_eos()')
>         self.kill()
>
>     def on_error(self, bus, msg):
>         print('on_error():', msg.parse_error())
>         self.kill()
>
>
> example = Example()
> example.run()
> ```
>
> But I got the same data like "FLV\0x01\0x01". Someone could answer the
> question?
>
>
>
> --
> Sent from: http://gstreamer-devel.966125.n4.nabble.com/
> _______________________________________________
> gstreamer-devel mailing list
> [hidden email]
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel

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[Yawei Wang]

How I get the continue stream data? Coulud you give me a support?

At 2018-01-12 11:10:14, "Matthew Waters" <[hidden email]> wrote:
>On 12/01/18 12:56, Yawei Wang wrote:
>> I use python to get data from appsink. My code is like below:
>> ```
>> import gi
>> gi.require_version('Gst', '1.0')
>> gi.require_version('GstApp', '1.0')
>> from gi.repository import GObject, Gst, GstApp
>>
>> GObject.threads_init()
>> Gst.init(None)
>>
>>
>> class Example:
>>     def __init__(self):
>>         self.mainloop = GObject.MainLoop()
>>         self.pipeline = Gst.Pipeline()
>>         self.bus = self.pipeline.get_bus()
>>         self.bus.add_signal_watch()
>>         self.bus.connect('message::eos', self.on_eos)
>>         self.bus.connect('message::error', self.on_error)
>>
>>         # Create elements
>>         self.src = Gst.ElementFactory.make('v4l2src', None)
>>         self.encoder = Gst.ElementFactory.make('x264enc', None)
>>         self.parse = Gst.ElementFactory.make('h264parse', None)
>>         self.mux = Gst.ElementFactory.make('flvmux', None)
>>         self.sink = Gst.ElementFactory.make('appsink', None)
>>
>>         # Add elements to pipeline
>>         self.pipeline.add(self.src)
>>         self.pipeline.add(self.encoder)
>>         self.pipeline.add(self.parse)
>>         self.pipeline.add(self.mux)
>>         self.pipeline.add(self.sink)
>>
>>         # Set properties
>>         self.src.set_property('device', "/dev/video0")
>>
>>         # Link elements
>>         self.src.link(self.encoder)
>>         self.encoder.link(self.parse)
>>         self.parse.link(self.mux)
>>         self.mux.link(self.sink)
>>
>>     def run(self):
>>         self.pipeline.set_state(Gst.State.PLAYING)
>>         # self.mainloop.run()
>>         appsink_sample = GstApp.AppSink.pull_sample(self.sink)
>
>This needs to be in the while loop below.
>
>What the code currently says is:
>1. Pull one sample
>2. While true, get the buffer from the sample (this will always return
>the same buffer).
>
>
>What you want is to pull_sample() inside the while loop
>>         while True:
>>             buff = appsink_sample.get_buffer()
>>             size, offset, maxsize = buff.get_sizes()
>>             frame_data = buff.extract_dup(offset, size)
>>             print(frame_data)
>>
>>     def kill(self):
>>         self.pipeline.set_state(Gst.State.NULL)
>>         self.mainloop.quit()
>>
>>     def on_eos(self, bus, msg):
>>         print('on_eos()')
>>         self.kill()
>>
>>     def on_error(self, bus, msg):
>>         print('on_error():', msg.parse_error())
>>         self.kill()
>>
>>
>> example = Example()
>> example.run()
>> ```
>>
>> But I got the same data like "FLV\0x01\0x01". Someone could answer the
>> question?
>>
>>
>>
>> --
>> Sent from: http://gstreamer-devel.966125.n4.nabble.com/
>> _______________________________________________
>> gstreamer-devel mailing list
>> [hidden email]
>> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
>
>

 

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[Yawei Wang]

OK I got it. I can use signal callback function to get the stream data. like below:

 

import gi

gi.require_version('Gst', '1.0')

gi.require_version('GstApp', '1.0')

from gi.repository import GObject, Gst, GstApp

GObject.threads_init()

Gst.init(None)

class Example:

    def __init__(self):

        self.mainloop = GObject.MainLoop()

        self.pipeline = Gst.Pipeline()

        self.bus = self.pipeline.get_bus()

        self.bus.add_signal_watch()

        self.bus.connect('message::eos', self.on_eos)

        self.bus.connect('message::error', self.on_error)

        # Create elements

        self.src = Gst.ElementFactory.make('v4l2src', None)

        self.encoder = Gst.ElementFactory.make('x264enc', None)

        self.parse = Gst.ElementFactory.make('h264parse', None)

        self.mux = Gst.ElementFactory.make('flvmux', None)

        self.sink = Gst.ElementFactory.make('appsink', None)

        # Add elements to pipeline

        self.pipeline.add(self.src)

        self.pipeline.add(self.encoder)

        self.pipeline.add(self.parse)

        self.pipeline.add(self.mux)

        self.pipeline.add(self.sink)

        # Set properties

        self.src.set_property('device', "/dev/video0")

        self.sink.set_property('emit-signals', True)

        # turns off sync to make decoding as fast as possible

        self.sink.set_property('sync', False)

        self.sink.connect('new-sample', self.on_new_buffer)

        # Link elements

        self.src.link(self.encoder)

        self.encoder.link(self.parse)

        self.parse.link(self.mux)

        self.mux.link(self.sink)

    def on_new_buffer(self, appsink):

        appsink_sample = GstApp.AppSink.pull_sample(self.sink)

        # with open('example.h264', 'a+') as streamer:

        buff = appsink_sample.get_buffer()

        size, offset, maxsize = buff.get_sizes()

        frame_data = buff.extract_dup(offset, size)

        print(size)

        # flag, info = buff.map(Gst.MapFlags.READ)

        # streamer.write(info.data)

        # print(info.size)

        return False

    def run(self):

        self.pipeline.set_state(Gst.State.PLAYING)

        self.mainloop.run()

    def kill(self):

        self.pipeline.set_state(Gst.State.NULL)

        self.mainloop.quit()

    def on_eos(self, bus, msg):

        print('on_eos()')

        self.kill()

    def on_error(self, bus, msg):

        print('on_error():', msg.parse_error())

        self.kill()

example = Example()

example.run()

At 2018-01-12 11:42:50, "black" <[hidden email]> wrote:

How I get the continue stream data? Coulud you give me a support?

At 2018-01-12 11:10:14, "Matthew Waters" <[hidden email]> wrote:
>On 12/01/18 12:56, Yawei Wang wrote:
>> I use python to get data from appsink. My code is like below:
>> ```
>> import gi
>> gi.require_version('Gst', '1.0')
>> gi.require_version('GstApp', '1.0')
>> from gi.repository import GObject, Gst, GstApp
>>
>> GObject.threads_init()
>> Gst.init(None)
>>
>>
>> class Example:
>>     def __init__(self):
>>         self.mainloop = GObject.MainLoop()
>>         self.pipeline = Gst.Pipeline()
>>         self.bus = self.pipeline.get_bus()
>>         self.bus.add_signal_watch()
>>         self.bus.connect('message::eos', self.on_eos)
>>         self.bus.connect('message::error', self.on_error)
>>
>>         # Create elements
>>         self.src = Gst.ElementFactory.make('v4l2src', None)
>>         self.encoder = Gst.ElementFactory.make('x264enc', None)
>>         self.parse = Gst.ElementFactory.make('h264parse', None)
>>         self.mux = Gst.ElementFactory.make('flvmux', None)
>>         self.sink = Gst.ElementFactory.make('appsink', None)
>>
>>         # Add elements to pipeline
>>         self.pipeline.add(self.src)
>>         self.pipeline.add(self.encoder)
>>         self.pipeline.add(self.parse)
>>         self.pipeline.add(self.mux)
>>         self.pipeline.add(self.sink)
>>
>>         # Set properties
>>         self.src.set_property('device', "/dev/video0")
>>
>>         # Link elements
>>         self.src.link(self.encoder)
>>         self.encoder.link(self.parse)
>>         self.parse.link(self.mux)
>>         self.mux.link(self.sink)
>>
>>     def run(self):
>>         self.pipeline.set_state(Gst.State.PLAYING)
>>         # self.mainloop.run()
>>         appsink_sample = GstApp.AppSink.pull_sample(self.sink)
>
>This needs to be in the while loop below.
>
>What the code currently says is:
>1. Pull one sample
>2. While true, get the buffer from the sample (this will always return
>the same buffer).
>
>
>What you want is to pull_sample() inside the while loop
>>         while True:
>>             buff = appsink_sample.get_buffer()
>>             size, offset, maxsize = buff.get_sizes()
>>             frame_data = buff.extract_dup(offset, size)
>>             print(frame_data)
>>
>>     def kill(self):
>>         self.pipeline.set_state(Gst.State.NULL)
>>         self.mainloop.quit()
>>
>>     def on_eos(self, bus, msg):
>>         print('on_eos()')
>>         self.kill()
>>
>>     def on_error(self, bus, msg):
>>         print('on_error():', msg.parse_error())
>>         self.kill()
>>
>>
>> example = Example()
>> example.run()
>> ```
>>
>> But I got the same data like "FLV\0x01\0x01". Someone could answer the
>> question?
>>
>>
>>
>> --
>> Sent from: http://gstreamer-devel.966125.n4.nabble.com/
>> _______________________________________________
>> gstreamer-devel mailing list
>> [hidden email]
>> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
>
>

 

 

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