Guideline for Smooth Streaming Application Developers¶
This document describes the features and the specification of Smooth Streaming.
When appending URL options, you don’t have to consider the sequence in case of optional attributes
Bitrate Range always takes priority over Startbitrate
The URL of Smooth Streaming
.isml/manifest is the url of live streaming. It is Case-Insensitive.
Set the initial Bitrate. Default value is LOWEST.
If the range of bitrate is set, the start bitrate follows the bitrate range.
Set the initial bitrate as the lowest bitrate
Set the initial bitrate as the average bitrate
Set the initial bitrate as the highest bitrate
Set the initial bitrate after checking N/W bandwidth
In case of ‘CHECK’, it takes 1.5 seconds normally.
Set the initial bitrate as the specific value
If there’s no value which equals the input value among bitrates, the start bitrate is set to the closest bitrate with the input value
Set the bitrate range
Example 1: http://10.88.73.127:8043/3/BigBuckBunny.ism/manifest|BITRATES=305000~937000
Example 2: http://10.88.73.127:8043/3/BigBuckBunny.ism/manifest|BITRATES=305000~937000|STARTBITRATE=532000
||SKIPBITRATE=||Set the bitrate value after skip. Default value is CHECK.||Optional|
Set skipbitrate by checking N/W bandwidth
Set skipbitrate as lowest bitrate
Set skipbitrate as average bitrate
Set skipbitrate as highest bitrate
||COOKIE=||Value||Set the COOKIE information||Optional|
- Adaptive Streaming
- It plays the stream with the bitrate selected basing on N/W bandwidth.
- Restriction on Seamless Change
- Video track is changed based on N/W bandwidth. The seamless changes are guaranteed when bitrate and resolution are changed.
- Audio track is not automatically changed based on N/W bandwidth. Even though N/W condition is changed, only video track is changed.
- Normal Play
- Play, Pause, Resume, Stop
- It skips 15 seconds forward/backward.
- It plays forward/backward 2x/4x/8x/16x faster than the original speed.
- When doing Trickplay, it plays with the lowest bitrate because of speed problem. So, the video quality is not good when doing Trickplay.
- After Trickplay, its resolution becomes higher and goes back to the bitrate as before trickplay
- It provides the function changing audio track.
- Audio track is changed only when a user changes codec, bitrate, channel and language options. When an audio option is changed, A/V data is flushed in buffer and start getting new stream from server. It possibly causes ‘Buffering’
- When an audio track is changed, Smooth Streaming Engine refers to manifest file(.ismc) to get Language, Channel, Codec and Bitrate information
- H.264 (up to email@example.com and reference frame should be less than 5 for supporting seamless stream change)
- AAC-LC, HE-AAC
- WMA (up to 10 Pro 5.1 channels, M2 profile. Except M0 LBR mode)
- The current DRM version is Playready 1.2 and DRM header 4.0