Format comparisons
Pick the right codec / container.
Honest side-by-side technical comparisons of the codec, container, and audio format choices that come up when downloading or working with video. Each comparison lists what each side genuinely wins on, with a practical verdict.
Video codec
AV1 vs H.264
AV1 is the modern royalty-free video codec (2018). H.264 is the universal compatibility codec (2003). The choice between them comes down to file size vs hardware support.
H.264 (AVC) vs H.265 (HEVC)
H.264 (AVC) is the universal video codec. H.265 (HEVC) is its successor — compresses ~50% better but has licensing complications that limited adoption.
VP9 vs AV1
VP9 was YouTube's modern royalty-free codec from 2013-2022. AV1 is its successor — better compression, royalty-free, gradually replacing VP9 across YouTube.
H.265 (HEVC) vs AV1
H.265 (HEVC) and AV1 are the two leading "next-generation" video codecs. Similar compression efficiency; different licensing models. AV1 is royalty-free; H.265 has tangled patent pools.
Audio format
MP3 vs m4a
MP3 is the universal audio format. m4a (AAC) is the modern more-efficient format. For YouTube specifically: m4a is YouTube's source audio; MP3 requires a transcode that loses quality.
WAV vs FLAC
WAV and FLAC are both lossless audio formats. WAV is uncompressed (raw PCM); FLAC is compressed losslessly. Same audio quality; FLAC files are ~50% smaller.
MP3 vs FLAC
MP3 is lossy, FLAC is lossless. The right pick depends on whether you care about audiophile-grade quality and have storage to spare.
Container format
MP4 vs MKV
MP4 is the universal video container. MKV (Matroska) is the flexible enthusiast container. The right pick depends on whether you prioritize compatibility or features.
WebM vs MP4
WebM is the open container Google created for web video (2010). MP4 is the universal container that came before (2003). For YouTube: WebM holds VP9/AV1+Opus; MP4 holds H.264/H.265+AAC.