Search the Internet Archive for “H.263 test clip” or “3GPP sample video.” While many are low-bitrate, filtering by file size (>2 MB) often reveals higher-quality outliers.
: Companies like Elecard provide high-quality encoded video files across various standards, including legacy formats, specifically for technical analysis. Getting the Most Out of Your Samples
It is computationally "light," making it ideal for devices with limited processing power where modern codecs might lag.
Use .3gp for mobile tests or .mov for desktop legacy support.
: Offers open-source software and might have sample clips.
Rather than searching for elusive legacy downloads, the most reliable way to get high-quality H.263 samples is to generate them yourself using modern tools: FFmpeg Conversion
: Offers a direct download for a standard bear.h263 sample file.