Answer: Video ratio: Video ratio refers to the ratio of the length and width of the video screen played by the video player. The ratio of the length to the width of the CRT TV used in ordinary households is 4:3, that is, the video ratio is 4:3. The currently developing high-definition display (TV and mobile) video ratio is 16:9. The current full-screen mobile phone is 17:9.

Answer: Common encoding method: VBR (Variable Bitrate) dynamic bit rate means that there is no fixed bit rate. The compression software immediately determines what bit rate to use according to the audio data when compressing. This is a method that takes into account the file size on the premise of quality. encoding mode;

ABR (Average Bitrate) is an interpolation parameter of VBR. LAME created this encoding mode in response to the poor file volume ratio of CBR and the variable size of VBR generated files. Within the specified file size, ABR takes every 50 frames (about 1 second for 30 frames) as a segment. Low-frequency and insensitive frequencies use relatively low traffic, and high-frequency and large dynamic performance use high traffic, which can be used as VBR and CBR. a compromise choice.

|CBR (Constant Bitrate), constant bit rate means that the file is a bit rate from the beginning to the end. Compared with VBR and ABR, the compressed file size is very large, and the sound quality will not be significantly improved compared with VBR and ABR.

A: Video packaging formats: WM (Windows Media Video), wmvhdMPEG (Moving Picture Experts Group), Matroska, Real VideoReal Media (RM), Real VideoReal Media (RM), OggMedia, etc.

Generally, the bit rate of high-definition movie MKV (BDrip-1080P) is about 10Mb/s, and the original Blu-ray disc is about 20Mb/s, both of which are H264 encoded. In addition to H264 encoding, some MVs, PVs, demos, etc. may also have MPEG-2 encoding, 1080P or 1080i, and the bit rate varies. Like those online 1080P videos on YouTube, the bit rate may only be 5Mb/s.

Answer: Types of optical fiber modules: Optical modules can be divided into SFP, eSFP, SFP+, XFP, SFP28, QSFP28, QSFP+, CXP, CFP, CSFP, etc.

Answer: Optical module rate classification: modules can be divided into 400Gbit/s optical modules, 200Gbit/s optical modules, 100Gbit/s optical modules, 40Gbit/s optical modules, 25Gbit/s optical modules, 10Gbit/s optical modules, 2.5Gbit/s optical modules s optical module, 1.25Gbit/s optical module, 1000Mbit/s optical module, 155Mbit/s, 100Mbit/s optical module, etc.

Answer: Single-fiber bidirectional refers to the simultaneous transmission and reception of optical signals in two directions in one optical fiber. The optical modules used in wireless devices are all optical transceiver modules. The dual-fiber bidirectional optical module has two optical fiber connection ports, while the single-fiber bidirectional optical module has only one optical fiber connection port. Single fiber bidirectional is mainly realized by WDM. The core device in the single-fiber bidirectional optical module is a 45° beam splitter. The light source irradiation surface of the beam splitter is coated with an anti-reflection film, and the reflective surface is coated with a reflective film. The composition and principle of the demultiplexer".

Answer: SH0201B USB hot key; S7211H USB2.0; S7201H USB hot key+USB2.0; S7201H2 dual display, USB hot key+USB2.0; S7215H2 dual display, USB hot key;