| Popis: |
Up to now, many existing video transmission and storage infrastructures are not able to handle UHD uncompressed video in real-time. For instance, the transmission of 4K UHD 4:2:2 10 bits 60p requires approximatively 4 times the bandwidth available on a 3-G SDI cable. To reduce the required bitrates, a low-latency lightweight compression scheme is needed. To this end, several standardization efforts such as Display Stream Compression (DSC), Advanced DSC and JPEG XS are currently undertaken. Focusing on the broadcast industry, this paper provides a comparison of existing codecs suited for this field of application. In particular, the performances of DSC, intoPIX TICO and JPEG 2000 are evaluated. Regarding JPEG2000, two flavours are used. First, the JP2K Ultra-Low Latency (ULL) used in the industry reaches a total latency of 0.5 frame by splitting each frame into 9 stripes (each of size 3840x240) that are independently encoded. To reach even lower latency and complexity, the paper defines the JP2K Ultra-Low Latency and Complexity (ULLC) which uses smaller stripes (each of size 3840x8) to have only 32 lines of latency. Regarding the experiment details, the objective metric used to assess the quality preservation is the Peak-Signal-to-Noise ratio. First, a quality assessment is realized in single and multiple generations. Then, the error robustness is evaluated by averaging over 1000 experiments the effect of inserting a one-bit error at a random position in the compressed bitstream. This experiment is meaningful since such bit-flip error occurs on SDI cable with a probability ranging from 10 -9 to 10 -12. From the results (displayed below), it appears that the coding schemes based on Discrete Wavelet Transform (namely TICO and JPEG 2000) give better results than DSC which is mainly based on intra-frame prediction methods. |
