H.263 is an ITU-T (International Telecommunication Union - Telecommunication Standardization Sector) video coding standard that was designed for low-bit-rate video communication. It was widely used in various applications, including video conferencing, video streaming over the internet, and as a part of 3GPP (3rd Generation Partnership Project) video telephony standards.

Dedicated media testing sites and software developers, such as , often host libraries of various video samples for encoding tests, sometimes including older formats like H.263. Pros: Varied container formats and resolutions. Cons: Requires sorting through many other formats. 3. Open Source Codec Repositories

: The original H.263 standard has several revisions (H.263+ and H.263++), which include optional "Annexes" (like Annex I or Annex J for advanced prediction). Ensure your test files do not include these features if your hardware only supports baseline H.263 profile 0.