[Libav-user] Dshow errors when trying to record desktop in Win 10

[Roger Pack]

this commit:

commit e82883aa88bfccf2669e914eab9deef6cecfd0db
Author: Matt Oliver <protogonoi at gmail.com>
Date:   Mon Oct 5 20:00:37 2015 +1100

modified how it uses dpi a bit may be related...

On 12/16/15, Casey Price <cprice1317 at gmail.com> wrote:
> I'm running ffmpeg 2.8.1 (I think, I know its not the latest since I
> grabbed it in October).
>
> I was able to resolve the issue by turning off screen-scaling in windows.
> By default its set to 150% on the surface Pro 3. If I didn't set a
> video_size the recording with screen scaling on it would only record a
> small portion of the top left hand corner of the screen (1280x853), so I
> believe the issue is with Dshow and screen scaling in windows 10 not
> playing together nicely.
>
> This fix works for me, but it would be nice if capturing would work with
> screen-scaling on since its quite hard to use the tablet with it off.
>
> On Tue, Dec 15, 2015 at 7:22 PM, Roger Pack <rogerdpack2 at gmail.com> wrote:
>
>> What version of ffmpeg are you using here? You should not have to
>> specify video_size by default it should capture the whole thing.
>>
>> On 12/14/15, Casey Price <cprice1317 at gmail.com> wrote:
>> > Hello,
>> >
>> > I'm currently trying to record the desktop of a surface pro 3 running
>> > windows 10 using screen-capture-recorder and ffmpeg. The following
>> > works
>> in
>> > the command line.
>> >
>> >      ffmpeg -f dshow -video_size 1280x853 -i
>> video=screen-capture-recorder
>> > output.mpg
>> >
>> > However when I try to do the same in code I get the error
>> >
>> >      '[dshow] Could not set video options'
>> >
>> > Which only happens when set the video_size option by doing the
>> > following:
>> >
>> >
>> >      av_dict_set(&dictionary, "video_size", "1280x853", NULL);
>> >
>> >      if ((ret = avformat_open_input(&ifmt_ctx, input_device,
>> > inputFormat,
>> > &dictionary)) < 0) {
>> > printf("Cannot open input file\n");
>> > return ret;
>> >      }
>> >
>> > I've also noticed that screen-capture-recorder says it only supports up
>> to
>> > 1280x853 video size when doing -list_options, even though the
>> > resolution
>> of
>> > the tablet in windows is 1920x1280, I think this is due to some
>> > software
>> > scaling that is going on with the surface, but not entirely certain
>> because
>> > the command line arguments that I posted above that works only records
>> the
>> > top left portion of the screen.
>> >
>> > Also, if I don't specify the video_size in the dictionary, the
>> > recording
>> > works but only records a portion of the desktop.
>> >
>> > Has anyone had an issue like this before? I'm not entirely certain if
>> > the
>> > issue lies with windows 10, directshow, screen-capture-recorder, or if
>> I'm
>> > just doing something wrong in my code.
>> >
>> > Thanks,
>> > Casey
>> >
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>