Suggest adding stream transcoding feature

[wuxianlijiang]

By using a configuration method similar to the existing "DVR" feature, transcode the specified stream or all streams and provide the transcoded stream and HLS address.

Expected configuration features:

Specify the stream to be transcoded
Specify transcoding parameters, such as: audio encoding, whether to convert to mono, sample rate, bit rate; video encoding, whether to keep the video, video frame rate, watermark, bit rate, frame size.

[winlinvip]

Fix in v5.10.11