- Constant Bitrate Encoded.
- Sample Rate a multiple of 11,025Hz. ie., 22,050Hz and 44,100Hz are valid sample rates.
M4a / M4v
The MP4 file is a container that supports both audio and video. The M4A format is an audio MP4, and the M4V format is a video MP4. The recommended encoding options for standard and mobile browsers are:
- H.264 Baseline Profile Level 3.0 video, up to 640 x 480 at 30 fps. Note that B frames are not supported in the Baseline profile.
- AAC-LC audio, up to 48 kHz.
The poster image should have the same aspect ratio as the player size, or the image will be distorted when it is resized to fit the area. Png and jpeg are accepted formats.
For a responsive image and to assure that it won't be distorted on larger screens use images of at least 1024 x 768 pixels (aspect ratio 16:9). Optimum image sizes are also 1920 x 1080 pixels. Lastly keep the images around to 100 KB to assure fast download into the player.