Video Compression

VideoNerd

Classification Visual Artifacts in Video Coding Systems

Content Blurring Color Bleeding Flickering Mosquito Noise       Ringing Blockiness Staircase           Motion Blur       Tearing   General Visual artifacts such as ringing, mosquito noise, flickering, blurring, blockiness etc. are caused directly or indirectly by the quantization in an encoder. Two types of video distortions are present: compression artifacts (due to lossy compression) and scaling […]

Visionular AV1 Codec versus HEVC Tesla T4 on Cloud Gaming Content

i compared Visionular AV1 codec (Aurora) against  Nvidia Tesla T4 HEVC encoder on cloud gaming content and found that AV1 is significantly better than HEVC. With the permission of Visionular i share the results of the comparison:   Conclusions: 1) On cloud gaming content AV1 Aurora reveals visual lossless coding (93 and above in VMAF) […]

On Finding Optimal CTU Partition in HEVC/H.265 

Content General HEVC CTU Partition Entropy-based method to get near-optimal CTU partition   General The main task for an HEVC, AV1 and VVC encoders is to decide how to partition each CTU in optimal way. A straightforward approach is to go through all available options and decide the optimal coding mode (i.e. the optimal partition) […]

How to Generate Skip Frame in H264/AVC and in HEVC

There is a notion as skip-frame in video coding – the frame which is exactly the same as the previous reference.   In screen coding and in computer graphics generated content skip frames are not uncommon.   How to generate skip-frame in H264 and in HEVC?   Two approaches:   1) P skip frame in H264 […]

Cloud Gaming Paradigm

Content What’s Cloud Gaming? History of Cloud Gaming Cloud Gaming in Details Cloud Gaming Problems Appendix A: Gaming content has unique characteristics different from live video Appendix B:  Temporal Masking Appendix C: the paper “A Network Analysis on Cloud Gaming: Stadia, GeForce Now and PSNow” Appendix D: the requirements for tolerable cloud gaming     […]

Reliable Video Coding for Medical Imaging

Definition: telemedicine is the remote provision of healthcare services that is done by transferring medical data on communication channels. Example: pre-hospital remote guidance to the in-ambulance paramedical staff from a physician.         Slides:   Reliable Video Coding for Medical Imaging         Lecture record               […]

Rate Control Et Cetera

Rate Control Issues: There are two main types of Rate Controls: CBR (Constant-Bitrate) and VBR (Variable-Bitrate).  In addition some encoders support CVQR (Constant Video Quality Rate Control), CVQR tries to keep constant visual quality. E.g. x264/x265 has a particular command-line parameter ‘-crf’ to specify CVQR mode and to keep a selected “visual quality”. A video […]

Does 60 Hz video require twice the bit rate of 30 Hz?

Is it correct to double the bandwidth when the frame rate of video stream is switched to 60Hz from 30Hz? Common sense says: if you double the number of frames then the bitrate should be also doubled. On the other hand, the temporal distance between frames in 60Hz is twice less than those of 30Hz. […]

Chicken and Egg Dilemma in Rate Control Implementations

The purpose of Rate Control is to determine a quantization parameter QP for a block (or for a frame) by using the MAD or SAD or other appropriate metric. On the other hand the MAD/SAD of the block (or the frame) can be computed only after determination of QP, because MAD (as well as SAD) […]

On Packet Duplication in Transport Stream

MPEG System standard (13818) allows packet to be duplicated, it says: “In transport streams, duplicate packets may be sent as two, and only two, consecutive transport stream packets of the same PID. The duplicate packets shall have the same continuity_counter value as the original packet and the adaptation_field_control field shall be equal to ’01’ or […]