To ensure that your TV Widget’s video works on all supported Connected TV devices, follow these encoding specifications:
Progressive download over HTTP is supported. Many encoders have an option to enable Internet streaming where the stream is buffered so that playback starts before the whole clip is fully downloaded.
Other supported streaming protocols vary by device. Currently one device partner supports MMS and other device partners will be supporting M3U8 and RTSP late in 2010 and early 2011. Existing devices can support a video playlist of URLs, but do not support a continuous open stream. The Yahoo! Widget Engine also supports redirection for the video playlist URLs.
The following encoding formats have been tested and work across all Connected TV devices:
- MP4 / H.264 / AAC — Recommended
- Container: MP4 (mpeg4)
- Codec: H.264
- Audio: AAC
- WMV9 / VC-1 / WMA
- Container: WMV9
- Codec: VC-1
- Audio: WMA
Constant/Variable Bit Rate
Optional. Both Constant Bit Rate (CBR) and Variable Bit Rate (VBR) are supported.
Multiple Video Bitrates
Yahoo! recommends choosing one resolution based on your source video’s size, and then encoding your videos in multiple bitrates to support varying connection bandwidth. The
KONtx.mediaplayer chooses the best stream given the current connection speed returned from
KONtx.speedtest. Support for the following video bitrates is recommended:
- 300 kbps
- 700 kbps
- 1000 kbps
- 2000 kbps — (for HD content only)
The recommended audio bitrate is 128 kbps for standard bitrate quality.
All devices are HD compatible and have a 16:9 aspect ratio. However, the device’s available network bandwidth limits HD resolution to 1280 x 720. PAL resolutions are supported. Depending on your content source, the following pixel resolutions are recommended:
- 640 x 360 — (medium quality 16:9)
- 640 x 480 — (medium quality 4:3)
- 720 x 480 — (high quality)
- 1280 x 720 — (for HD content only)
Optional. Typical frame rates of 29.97 fps for video-based source material and 23.97 fps for film-based source material are supported.
— Jim Cortez and the Yahoo! Connected TV Team
To see additional tips for testing video go to the Development FAQ→Video/Audio/Media Player section.
Please also search for video posts in the Connected TV Developer forums: http://developer.yahoo.net/forum/?showforum=91