What is the difference between H.264 and H.265.
1 Answer
  • High Efficiency Video Coding (HEVC), or H.265, is a video compression standard designed to substantially improve coding efficiency when compared to its precedent, the Advanced Video Coding (AVC), or H.264. With an increasing growth of video streaming on the Internet and with 4K cameras gaining new ground in the market, a considerable amount of storage and bandwidth is required.
  • HEVC promises a 50% storage reduction as its algorithm uses efficient coding by encoding video at the lowest possible bit rate while maintaining a high image quality level. With this new format, image resolutions around 8192×4320 become possible to display and stream.
  • HEVC/H.265 not only has a better visual quality at a low storage and bandwidth but also a dexterously coding algorithm by encoding motion vectors with much greater precision and minimal residual errors.
  • HEVC/H.265 comes with the trade-off requiring almost 10x more computing power. This new technology is on standby until the hardware market adapts to it, as it happened already with H.264.
  • Even though some softwares such as VideoLAN are capable to decode such codec, software decoding, although more flexible, is not an option since hardware decoding is usually faster and saves battery life tremendously.

Comparison of H.264 and H.265

Sr. No. Parameters H.264 H.265
1. Bit Reduction 40-50% bit rate compared to MPEG-2 40-52% reduction at same quality compared to H.264
2. Specification Support upto 4K Support upto 8K
3. Bandwidth required to broadcast 4K 32 Mbps 15 Mbps
4. Compression Model Hybrid Spatial-temporal prediction model.; Flexible partition of Macro Block (MB), Sub MB for motion estimation; Intra Prediction (extrapolate already decoded neighboring pixels for prediction); Introduced multi-view extension 9 directional modes for intra prediction; Macro Blocks structure with maximum size of 16x16 ; Entropy coding is CABAC and CAVLC Enhanced Hybrid spatial-temporal prediction model; Flexible partitioning, introduces Coding Tree Units (Coding, Prediction and Transform Units -CU, PU, TU); 35 directional modes for intra prediction; Superior parallel processing architecture, enhancements in multi-view coding extension; CTU supporting larger block structure (64x64) with more variable sub partition structures; Entropy coding is only CABAC
5. Industry adoption Dominant and accepted video codec for Terrestrial, Cable, Satellite and IPTV broadcast. (ATSC/DVB/ISDB); Widely used across Blu-Ray, security systems, videoconferencing , mobile video, media players, video chat etc Implementation demonstration across NAB, IBC and other events starting 2012 from companies e.g. ATEME, Broadcom, Thomson , Harmonic (Cisco), Ericsson, Qualcomm etc. ; Increased R&D across Encoder/Decoder /CE vendors for software and hardware based solutions
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