winapi - 使用 DirectShow 的视频录制分辨率

Question

在 directshow 中录制时如何更改视频的屏幕分辨率？因为我有一个 8 兆像素的网络摄像头，我用它来录制视频，但在保存视频后，当我查看视频时，播放起来就像是使用 1.3 兆像素的摄像头录制的。

Answer 1

您需要使用IAMStreamConfig 接口(interface)。为您提供一些 MSDN 线索:

Configure the Video Output Format (Windows) :

To configure a capture device's output format, an application should use the AM_MEDIA_TYPE structure returned by IAMStreamConfig::GetFormat in the pmt parameter.

IAMStreamConfig::GetFormat method (Windows) :

If the pin is connected, this method returns the format that the pin is currently using. Otherwise, the method returns the pin's preferred format for the next pin connection. If you have already called the IAMStreamConfig::SetFormat method to set the format, GetFormat returns the same format. If not, it returns the first format in the pin's list of preferred formats, as determined by the IPin::EnumMediaTypes method.

更多:

• how to change OutPut Pin Size & ColorSpace/Compression in DirectShow
• How can i Programmatically set a Directshow Filters' options?
• DirectShow - Order of invocation of IAMStreamConfig::SetFormat and ICaptureGraphBuilder2::RenderStream creates issues in some video cameras

此外，由于后处理功能，您的网络摄像头的视频流分辨率可能较低，而静止图像的分辨率可能较高。