[Ffmpeg-devel] [PATCH] Allow choosing display and screen number for x11grab device

[Michael Niedermayer]

Hi

On Wed, Dec 13, 2006 at 10:28:11PM +0100, Panagiotis Issaris wrote:
> Hi,
> 
> The attached patch allows one to provide the displaynumber.screennumber
> parameters to the x11grab device, for example:
> ffmpeg -vd x11:0.1 -s 640x480 test.avi
> 
> Currently the docs stated this was already the case, but that was incorrect. The
> parameters that currently were parsed were used as an offset within the screen
> for doing the grabbing. I've taken the usual '+' as a separator for still being
> able to provide that offset. If no offset is provided, 0,0 is taken by
> default.
> 
> So, to grab from display number 0, screen number 1 and start grabbing at
> location (10,20), use:
> ffmpeg -vd x11:0.1+10,20 -s 640x480 test.avi
> 
> With friendly regards,
> Takis

[...]
> Index: libavformat/x11grab.c
> ===================================================================
> --- libavformat/x11grab.c	(revision 7317)
> +++ libavformat/x11grab.c	(working copy)
> @@ -94,21 +94,33 @@
>      int x_off = 0;
>      int y_off = 0;
>      int use_shm;
> +    char *param, *offset;
>  
> -    dpy = XOpenDisplay(NULL);
> -    if(!dpy) {
> +    if (!ap->device) {
> +        av_log(s1, AV_LOG_ERROR, "AVParameters don't specify any device. Use -vd.\n");
> +        return AVERROR_IO;
> +    }
> +
> +    param = strchr(ap->device, ':');
> +    if (!param) {
>          av_free(st);
>          return AVERROR_IO;
>      }
> +    
> +    offset = strchr(param, '+');
> +    if (offset) {
> +        sscanf(offset, "%d,%d", &x_off, &y_off);
> +        *offset = 0;

hmm that writes into ap->device, why?

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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