[FFmpeg-devel] [PATCH] avdevice/avfoundation: add scaleFactor attribute for avfoundation

[Saeid Zangeneh]

thanks
but i'm using linux ubuntu system.


On Tue, Aug 1, 2017 at 1:03 AM, Thilo Borgmann <thilo.borgmann at mail.de>
wrote:

> Am 31.07.17 um 17:34 schrieb sharpbai:
> > From: sharpbai <tian.bai at duobei.com>
> >
> > feature: add scaleFactor attribute for avfoundation
> > added by: siyuan.wang at duobei.com
> > added by: yiren.li at duobei.com
> > ---
> >  doc/indevs.texi            | 6 ++++++
> >  libavdevice/avfoundation.m | 8 ++++++++
> >  2 files changed, 14 insertions(+)
> >
> > diff --git a/doc/indevs.texi b/doc/indevs.texi
> > index 09e3321..3d25930 100644
> > --- a/doc/indevs.texi
> > +++ b/doc/indevs.texi
> > @@ -139,6 +139,12 @@ Capture the mouse pointer. Default is 0.
> >  @item -capture_mouse_clicks
> >  Capture the screen mouse clicks. Default is 0.
> >
> > + at item -scale_factor
> > +Scale factor for capture the screen. Set this property to scale the
> buffers
> > +by a given factor. For example a 320x240 capture area with a
> scale_factor of 2.0
> > +produces video buffers at 640x480. Another example a 320x240 capture
> area with
> > +a scale_factor of 0.5 produces video buffers at 160x120. Default is 1.0
> (no scaling).
> > +
>
> Copy & Paste from the Apple's reference is hardly what is expected, please
> find your own wording.
> Adding an example would be nice.
> Maybe even renaming the option or state more implicitly that this option
> is for screen recording only.
>
> How does it work?
>
> At least for me, this
> "ffmpeg -f avfoundation -video_device_index 0 -scale_factor 1.5 -i ""
> out.avi"
> produces the same output resolution and viewport like that
> "ffmpeg -f avfoundation -video_device_index 0 -scale_factor 1.0 -i ""
> out.avi".
> What am I missing?
> Some previous questions remain, about factor > 2.0 and factor < 1.0?
>
>
> >  @end table
> >
> >  @subsection Examples
> > diff --git a/libavdevice/avfoundation.m b/libavdevice/avfoundation.m
> > index e2ddf47..3764de8 100644
> > --- a/libavdevice/avfoundation.m
> > +++ b/libavdevice/avfoundation.m
> > @@ -96,6 +96,7 @@ typedef struct
> >
> >      int             capture_cursor;
> >      int             capture_mouse_clicks;
> > +    float           scale_factor;
> >
> >      int             list_devices;
> >      int             video_device_index;
> > @@ -735,6 +736,12 @@ static int avf_read_header(AVFormatContext *s)
> >                  capture_screen_input.minFrameDuration =
> CMTimeMake(ctx->framerate.den, ctx->framerate.num);
> >              }
> >
> > +            if (ctx->scale_factor <= 2.0 && ctx->scale_factor > 0.0) {
> > +                capture_screen_input.scaleFactor = ctx->scale_factor;
> > +            } else {
> > +                av_log(ctx, AV_LOG_ERROR, "The value of scale_factor
> must be more than 0.0 and less than or equal to 2.0");
> > +            }
> > +
>
> I'm quite sure this is not what was meant to be checked.
> Also, the range of this option is already guarded when reading it from the
> command line, you don't have to take care about out of limits here.
>
>
>
> >  #if !TARGET_OS_IPHONE && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1080
> >              if (ctx->capture_cursor) {
> >                  capture_screen_input.capturesCursor = YES;
> > @@ -1025,6 +1032,7 @@ static const AVOption options[] = {
> >      { "video_size", "set video size", offsetof(AVFContext, width),
> AV_OPT_TYPE_IMAGE_SIZE, {.str = > NULL}, 0, 0, AV_OPT_FLAG_DECODING_PARAM },
> >      { "capture_cursor", "capture the screen cursor",
> offsetof(AVFContext, capture_cursor), AV_OPT_TYPE_INT, {.i64=0}, 0, 1,
> AV_OPT_FLAG_DECODING_PARAM },
> >      { "capture_mouse_clicks", "capture the screen mouse clicks",
> offsetof(AVFContext, > capture_mouse_clicks), AV_OPT_TYPE_INT, {.i64=0}, 0,
> 1, AV_OPT_FLAG_DECODING_PARAM },
> > +    { "scale_factor", "scale screen factor range", offsetof(AVFContext,
> scale_factor),
>
> It is not a range but the value (within a range) defining the scale factor
> of screen recording.
> Also find something more precisely here, please.
>
>
> > AV_OPT_TYPE_FLOAT, {.dbl=1.0}, 0.0, 2.0, AV_OPT_FLAG_DECODING_PARAM },
> >
> >      { NULL },
> >  };
> >
>
> -Thilo
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