Always use getResourcePath() to get the appropriate path to these resources depending on the context (WPT, standalone, worker, etc.)

The test video files were generated with by ffmpeg cmds below:

// Generate four-colors-vp8-bt601.webm, mimeType: 'video/webm; codecs=vp8'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv four-colors-vp8-bt601.webm

// Generate four-colors-h264-bt601.mp4, mimeType: 'video/mp4; codecs=avc1.4d400c'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libx264 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv four-colors-h264-bt601.mp4

// Generate four-colors-vp9-bt601.webm, mimeType: 'video/webm; codecs=vp9'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx-vp9 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv four-colors-vp9-bt601.webm

// Generate four-colors-vp9-bt709.webm, mimeType: 'video/webm; codecs=vp9'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx-vp9 -pix_fmt yuv420p -frames 50 -colorspace bt709 -color_primaries bt709 -color_trc bt709 -color_range tv -vf scale=out_color_matrix=bt709:out_range=tv four-colors-vp9-bt709.webm

// Generate  four-colors-vp9-bt601.mp4, mimeType: 'video/mp4; codecs=vp9'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx-vp9 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv four-colors-vp9-bt601.mp4

Generate video files to test rotation behaviour. Use ffmepg to rotate video content x degrees in cw direction (by using transpose) and update transform matrix in metadata through display_rotation to x degrees to apply ccw direction rotation.

H264 rotated video files are generated by ffmpeg cmds below:

// Generate four-colors-h264-bt601-rotate-90.mp4, mimeType: 'video/mp4; codecs=avc1.4d400c'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libx264 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv -vf transpose=2 temp.mp4
ffmpeg -display_rotation 270 -i temp.mp4 -c copy four-colors-h264-bt601-rotate-90.mp4
rm temp.mp4

// Generate four-colors-h264-bt601-rotate-180.mp4, mimeType: 'video/mp4; codecs=avc1.4d400c'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libx264 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv -vf transpose=2,transpose=2 temp.mp4
ffmpeg -display_rotation 180 -i temp.mp4 -c copy four-colors-h264-bt601-rotate-180.mp4
rm temp.mp4

// Generate four-colors-h264-bt601-rotate-270.mp4, mimeType: 'video/mp4; codecs=avc1.4d400c'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libx264 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv -vf transpose=1 temp.mp4
ffmpeg -display_rotation 90 -i temp.mp4 -c copy four-colors-h264-bt601-rotate-270.mp4
rm temp.mp4

Vp9 rotated video files are generated by ffmpeg cmds below:

// Generate four-colors-vp9-bt601-rotate-90.mp4, mimeType: 'video/mp4; codecs=vp9'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx-vp9 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv -vf transpose=2 temp.mp4
ffmpeg -display_rotation 270 -i temp.mp4 -c copy four-colors-vp9-bt601-rotate-90.mp4
rm temp.mp4

// Generate four-colors-vp9-bt601-rotate-180.mp4, mimeType: 'video/mp4; codecs=vp9'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx-vp9 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv -vf transpose=2,transpose=2 temp.mp4
ffmpeg -display_rotation 180 -i temp.mp4 -c copy four-colors-vp9-bt601-rotate-180.mp4
rm temp.mp4

// Generate four-colors-vp9-bt601-rotate-270.mp4, mimeType: 'video/mp4; codecs=vp9'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx-vp9 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv -vf transpose=1 temp.mp4
ffmpeg -display_rotation 90 -i temp.mp4 -c copy four-colors-vp9-bt601-rotate-270.mp4
rm temp.mp4

Generate video files to test flip behaviour. Use ffmpeg to flip video content. Using display_hflip to do horizontal flip and display_vflip to do vertical flip.

H264 flip video files are generated by ffmpeg cmds below:

// Generate four-colors-h264-bt601-hflip.mp4, mimeType: 'video/mp4; codecs=avc1.4d400c'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libx264 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv temp.mp4
ffmpeg -display_hflip -i temp.mp4 -c copy four-colors-h264-bt601-hflip.mp4
rm temp.mp4

// Generate four-colors-h264-bt601-vflip.mp4, mimeType: 'video/mp4; codecs=avc1.4d400c'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libx264 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv temp.mp4
ffmpeg -display_vflip -i temp.mp4 -c copy four-colors-h264-bt601-vflip.mp4
rm temp.mp4

Vp9 flip video files are generated by ffmpeg cmds below:

// Generate four-colors-vp9-bt601-hflip.mp4, mimeType: 'video/mp4; codecs=vp09.00.10.08'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx-vp9 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv temp.mp4
ffmpeg -display_hflip -i temp.mp4 -c copy four-colors-vp9-bt601-hflip.mp4
rm temp.mp4

// Generate four-colors-vp9-bt601-vflip.mp4, mimeType: 'video/mp4; codecs=vp09.00.10.08'
ffmpeg.exe -loop 1 -i .\four-colors.png -c:v libvpx-vp9 -pix_fmt yuv420p -frames 50 -colorspace smpte170m -color_primaries smpte170m -color_trc smpte170m -color_range tv temp.mp4
ffmpeg -display_vflip -i temp.mp4 -c copy four-colors-vp9-bt601-vflip.mp4
rm temp.mp4