VLC starts removing modules when "stop" is issued .. and freezes ("xcb_xv")

[sampsa]

Hello,

I am building a python application that opens several vlc instances and for each of them a player object.

Players show their stuff inside qt widgets in my python/qt based application.

Unfortunately, stopping the players, causes the program occasionally to freeze. I have traced down this behaviour to the fact, that each time a player object receives a "stop" command, it starts to remove modules..! (why it removes them, btw!?)

One can confirm this behaviour by starting the stock vlc player at the command line with the "-vvv" option and pressing "stop"

[0xf63b88] main playlist debug: incoming request - stopping current input
[0x7f92e4002e88] main input debug: control: stopping input
[0x7f92b0001248] main vout display debug: auto hiding mouse cursor
[0xf63b88] main playlist debug: incoming request - stopping current input
[0xf63b88] main playlist debug: finished input
[0x7f92d0c0b198] main decoder debug: removing module "avcodec"
[0x7f92d0c0b198] avcodec decoder debug: ffmpeg codec (H264 - MPEG-4 AVC (part 10)) stopped
[0x7f92d0c0b198] main decoder debug: killing decoder fourcc `h264', 0 PES in FIFO
[0xf63b88] main playlist debug: saving a free vout
[0xf63b88] main playlist debug: reusing provided vout
[0x7f92d0c1f3a8] main decoder debug: removing module "g711"
[0x7f92d0c1f3a8] main decoder debug: killing decoder fourcc `mlaw', 0 PES in FIFO
[0x7f92c0002f78] main audio resampler debug: removing module "ugly_resampler"
[0x7f92c0000958] main volume debug: removing module "integer_mixer"
[0xf63b88] main playlist debug: keeping audio output
[0x7f92d0c01878] main demux debug: removing module "mkv"
[0x7f92e4002e88] main input debug: Program doesn't contain anymore ES
[0x7f92d0c01878] mkv demux debug: Stopping the UI Hook
[0x7f92d0c015d8] main stream debug: removing module "record"
[0x7f92d00011f8] main access debug: removing module "filesystem"
[0xf63b88] main playlist debug: incoming request - stopping current input
[0xf63b88] main playlist debug: dead input
[0x7f92b801ec68] main video output debug: destroying useless vout
[0xf7f5e8] qt4 interface debug: IM: Deleting the input
[0x7f92b00101c8] main blend debug: removing module "blend"
[0x7f92b0001248] main vout display debug: removing module "xcb_xv"
[0x7f92b0004318] dbus_screensaver inhibit debug: got cookie 12712
[0x7f92b0004318] main inhibit debug: removing module "dbus_screensaver"

I have traced down the freezing of my python program to the line

main vout display debug: removing module "xcb_xv"

.. after that, the program freezes for a looong while, and suddenly comes back to life.

I started issuing "pause" to the player objects instead of "stop" (fixes the freezing problem), but this approach has its own quirks as well .. for example, there is no way to hide the video from the qt widget..! (issuing "stop", stops displaying video in the widget).

So, my actual questions are:

- Any way to tell vlc not to start removing modules when stopping a video stream ?
- Why does it freeze when mingling with xcb_xv ?
- Any way to hide the video from an X window after issuing the player a "pause" command ?

I am using VLC 2.2 with hardware acceleration (VDPAU)

Regards,

Sampsa

[Rémi Denis-Courmont]

No.
A stack trace would tell you.
Unmap the window.

[sampsa]

Remi, thanks for the prompt replay, but ..

.. unmap the window?

player.set_xwindow(0)
player.set_xwindow(None)

.. or what? (the above examples don't work)

Of course, I can issue "hide" for the QWidget in Qt .. for several reasons (not explained here) I'd like to avoid that ..
.. is that what you ment?

.. or, of course, map it to a different window and then keep that "dummywindow" always hidden.

I realized that you are in Helsinki. May I buy you an (expensive) beer some day?

[Rémi Denis-Courmont]

Unmapping the window is an X11 protocol operation that retains the window identifier but removes the window from display until it is mapped again. It does not involve LibVLC. What that corresponds to, in your specific choice of high-level GUI framework, I do not necessarily know.