H.264 / H.265
Also known as: AVC, HEVC, H.264 AVC, H.265 HEVC, libx264, libx265
H.264 (AVC) and H.265 (HEVC) are video codecs -- algorithms that compress video for storage and streaming.
H.264 is the most widely supported codec, used everywhere from YouTube to Blu-ray. H.265 cuts file sizes in half at equivalent quality, enabling 4K streaming, but its patent licensing fees slowed adoption and gave rise to open alternatives like AV1.
H.264 / H.265, explained at three levels
At home
Video codecs compress video so it can be stored and streamed without impossibly large files. H.264 is the codec behind most online video today. H.265 uses half the data for the same quality -- useful for 4K video where file sizes would otherwise be enormous.
At work
When encoding video for streaming, storage, or delivery, choosing the right codec affects file size, quality, and compatibility. H.264 plays everywhere. H.265 reaches a smaller but growing number of devices and reduces storage and bandwidth costs for 4K and above.
At home
Both codecs use temporal compression: rather than storing every frame completely, they store reference frames (I-frames) and encode subsequent frames as differences (P-frames, B-frames). H.265 uses larger coding tree units (up to 64x64 pixels vs. H.264's 16x16 macroblocks) and more sophisticated prediction, achieving better compression, especially at high resolutions.
At work
Encoding H.265 requires more CPU/GPU time than H.264. Decoding H.265 requires hardware support (most devices since 2016 have it, but older devices may struggle). Streaming platforms choose based on the device mix: YouTube defaults to AV1 for Chrome/Android; Netflix uses H.264 for broad compatibility, H.265 for 4K HDR, and AV1 for compatible devices.
At home
H.264 profiles (Baseline, Main, High) define feature subsets for different device capabilities. H.265 profiles (Main, Main 10) add 10-bit color support for HDR. Both use an encoder CRF (Constant Rate Factor) or bitrate target to control quality. At the same visual quality (SSIM/VMAF), H.265 achieves 40-50% bitrate reduction over H.264 on typical content.
At work
HEVC (H.265) royalty complexity led multiple licensors (MPEG LA, HEVC Advance, Velos Media) to each claim royalties, creating stacking fees that made commercial deployment unpredictable. This directly motivated AOM's development of AV1. FFmpeg and libx264/libx265 are the standard open-source encoders. VAAPI, NVENC, and VideoToolbox provide GPU-accelerated encoding on AMD, NVIDIA, and Apple hardware respectively.
Real-world examples
At home
Marcus records 4K video on his iPhone. The camera uses H.265 (HEVC) by default, cutting file sizes roughly in half compared to H.264. When he shares clips, he re-encodes to H.264 for maximum compatibility with older devices.
At work
Jerome's media company transcodes uploaded videos into multiple formats: H.264 for broad compatibility, H.265 for 4K streams on supported devices, and AV1 for Chrome users where the encoder cost is justified by bandwidth savings at scale.
How it compares
| feature | H.264 | H.265 |
|---|---|---|
| Standardized | 2003 | 2013 |
| Compression vs H.264 | Baseline | ~50% better |
| Licensing | MPEG LA (single pool) | Multiple pools (complex) |
| Hardware decode support | Universal | Devices from ~2016+ |
| Common use | Web, broadcast, Blu-ray | 4K streaming, HDR content |
For analysts
Video codec choice has real business implications -- H.265 cuts CDN bandwidth costs by up to 50% at 4K but requires compatibility testing. BAs working in media or e-learning platforms should understand codec tradeoffs when evaluating streaming infrastructure costs.
History & origin
H.264 was standardized in 2003 by the ITU-T and ISO/IEC jointly and became the dominant video codec for a decade, replacing MPEG-2 in streaming, broadcast, and Blu-ray. H.265 (HEVC) was standardized in 2013 with twice the compression efficiency, but fragmented patent pools from multiple licensing bodies created uncertainty. This opened the door for AV1, an open-source royalty-free codec developed by the Alliance for Open Media (AOM, including Google, Netflix, Amazon, and Apple).