[vlc-devel] [PATCH] v4l2 mpeg2 controls

Antoine Cellerier dionoea at videolan.org
Tue Jan 8 21:23:31 CET 2008


On Tue, Jan 08, 2008, Dennis Lou wrote:
> MPEG2 controls on Ext. Settings panel made it ~2000 pixels tall so I
> took it out and set those parameters by string instead. Making a linked
> list of available controls may help in the future with probing the
> device and setting parameters before opening stream, especially since
> MPEG parameters cannot be changed mid-stream.

Are all MPEG parameters pre-stream? or can some still be changed while
the stream is playing (like if you want to tweak the bitrate a bit or
some encoder setting)? (I'd have to get an MPEG encoding card to test)

I also have a few comments about the patch itself:

> +    add_integer( CFG_PREFIX "audio-volume", -1, NULL, AUDIO_VOLUME_TEXT,
> +                AUDIO_VOLUME_LONGTEXT, VLC_TRUE );
> +    add_integer( CFG_PREFIX "audio-balance", -1, NULL, AUDIO_BALANCE_TEXT,
> +                AUDIO_BALANCE_LONGTEXT, VLC_TRUE );
> +    add_bool( CFG_PREFIX "audio-mute", VLC_FALSE, NULL, AUDIO_MUTE_TEXT,
> +              AUDIO_MUTE_LONGTEXT, VLC_TRUE );

Is there any reason why you left the 3 other audio controls out? (I
didn't include audio controls in the first place since I didn't know if
they were used by any v4l2 driver ...)

> +static void ControlDebugPrint( vlc_object_t *p_obj, int i_fd,
> +                              struct v4l2_queryctrl queryctrl )

Wouldn't it be possible to somehow merge this function with
ControlListPrint ? (as far as I can see it's the same function without
any of the VLC variables creation code)

The --v4l2-reset-controls switch options isn't taken into account for
MPEG class controls.

That must be about it.


Antoine Cellerier

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