H.264 is a video compression standard is widely used for recording, compressing, and distributing video content.
SVC (Scalable Video Coding) enables the encoding of a high-quality H.264 bitstream that also contains one or more subset bitstreams, including a “base layer” bitstream that can be decoded by a H.264 decoder that does not support SVC. A subset H.264 bitstream is created by dropping packets from a larger H.264 bitstream to reduce the bandwidth required for the subset bitstream. The subset bitstream can represent a smaller picture, lower frame rate, or lower image quality compared to the bitstream it is derived from.
H.265 (or known as HEVC – High Efficiency Video Coding) is a video compression standard similar to H.264 but supports block size of up to 64×64 as compared to H.264 which allows maximum block size of 16×16.
This results in significant improvement with better motion compensation and spatial predictions, compression ratio is almost double at the same level of video quality, significant improvement in video quality at the same bitrate as H.264, supports resolutions up to 8192×4320, including 8K UHD.
However, the demand placed on the hardware for signal processing is also significantly higher.