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

[Steven Liu]

2017-07-31 21:32 GMT+08:00 sharpbai <sharpbai at gmail.com>:
> 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 | 6 ++++++
>  2 files changed, 12 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).
> +
>  @end table
>
>  @subsection Examples
> diff --git a/libavdevice/avfoundation.m b/libavdevice/avfoundation.m
> index e2ddf47..1aec234 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 +736,10 @@ static int avf_read_header(AVFormatContext *s)
>                  capture_screen_input.minFrameDuration = CMTimeMake(ctx->framerate.den, ctx->framerate.num);
>              }
>
> +            if (ctx->scale_factor != 1 && ctx->scale_factor > 0) {
if the scale_factor is fload, this check maybe need attention, about
code secure

> +                capture_screen_input.scaleFactor = ctx->scale_factor;
> +            }
> +
>  #if !TARGET_OS_IPHONE && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1080
>              if (ctx->capture_cursor) {
>                  capture_screen_input.capturesCursor = YES;
> @@ -1025,6 +1030,7 @@ 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), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0, 2, AV_OPT_FLAG_DECODING_PARAM },
As Thilo's suggest, this default maybe 1.0 better.

>
>      { NULL },
>  };
> --
> 2.2.1
>
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