Video codec system and video stream transmission method

A video codec system, comprising:

• a video encoding apparatus, comprising:
• a first video processor configured to encode a plurality of first images to generate a video bitstream;
• a first memory unit configured to store the video bitstream;
• and
• a first network unit configured to transmit the video bitstream over a network;
• and
• a video decoding apparatus, comprising:
• a second network unit configured to receive the video bitstream;
• a second video processor configured to decode the video bitstream to generate a plurality of second images correspondingly;
• and
• a second memory unit configured to store the second images,
• wherein when the second video processor detects that there is data loss of the video bitstream during transmission, the second video processor references a third image, which is the most recent completely decoded image of the plurality of second images, to perform subsequent video decoding processes, and transmits a request signal to the video encoding apparatus, so that the first video processor references a fourth image, which corresponds to the third image, of the plurality of first images, to perform subsequent video encoding processes.