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Adaptive streaming HLSv4 and MPEG-DASH on TVIPSTB
HLS v4
Initiated by using URL scheme hlsv4 or hlsv4s.
Feature set list is based on RFC8216
3.1. Supported Media Segment Formats
3.2 MPEG-2 Transport Streams
Tested: H.264, HEVC, AAC, AC3, MPEG Audio.
Untested, but planned: EAC3, DTS.
Not planned to support: MPEG2, MPEG4.
EXT-X-MAP is not supported for MPEGTS.
TS segment should contain no more the one video and one audio track.
3.3 Fragmented MPEG-4
Tested: H.264, HEVC, AAC.
Untested, but planned: AC3, EAC3, DTS.
Planned to support: VP9.
EXT-X-MAP is supported for initialization segment.
fMP4 segment should contain only a single stream (audio or video)
3.4 Packed audio
Tested: AAC.
Planned: AC3, EAC3.
3.5 WebVTT
Basic support for wtt segments in VoD.
4.3.2 Media Segment Tags
4.3.2.1 EXTINF
Supported.
4.3.2.2 EXT-X-BYTERANGE
Supported.
4.3.2.3 EXT-X-DISCONTINUITY
Supported, but player reaction is limited.
4.3.2.4 EXT-X-KEY
Supported.
Attributes: URI, IV, KEYFORMAT.
AES-128 is supported.
SAMPLE-AES is supported for MPEGTS.
CENC for fMP4 is planned.
4.3.2.5 EXT-X-MAP
Supported for fMP4. Only unencrypted.
4.3.2.6 EXT-X-PROGRAM-DATE-TIME
Supported.
Can be used for timeshifting.
4.3.2.7 EXT-X-DATERANGE
Not supported.
4.3.3 Media Playlist Tags
4.3.3.1 EXT-X-TARGETDURATION
Supported.
4.3.3.1 EXT-X-MEDIA-SEQUENCE
Supported.
4.3.3.3 EXT-X-DISCONTINUITY-SEQUENCE
Supported, but player reaction is limited.
4.3.3.4 EXT-X-ENDLIST
Supported.
4.3.3.5 EXT-X-PLAYLIST-TYPE
Supported.
4.3.3.6 EXT-X-I-FRAMES-ONLY
Not supported.
4.3.4 Master Playlist Tags
Supported.
4.3.4.1 EXT-X-MEDIA
Supported.
Valid TYPE values: AUDIO, VIDEO, SUBTITLES.
Supported attributes: TYPE, URI, GROUP-ID, LANGUAGE, NAME
4.3.4.1.1 Rendition Groups
Supported.
4.3.4.2 EXT-X-STREAM-INF
Supported.
Supported attributes: BANDWIDTH,CODECS,AUDIO,VIDEO,SUBTITLES.
4.3.4.3 EXT-X-I-FRAME-STREAM-INF
Not supported.
4.3.4.4 EXT-X-SESSION-DATA
Not supported.
4.3.4.5 EXT-X-SESSION-KEY
Not supported.
4.3.5 Media or Master Playlist Tags
4.3.5.1 EXT-X-INDEPENDENT-SEGMENTS
Not supported.
4.3.5.2 EXT-X-START
Not supported.
6.3 Client Responsibilities
6.3.3 Playing the Media Playlist File
EXT-X-PROGRAM-DATE-TIME is only forward exterpolated.
MPEG-DASH
MPEG-DASH support will be based on : DASH-IF interop guideline.
Currently support is limited:
- VOD profile and some subset of Live profile are supported.
- Media segments should be MP4 (CMAF) with H264/H265 video and AAC/AC3 audio. WebM segment support is planned.
- Media should be either splitted into file segments and use SegmentTemplate tag, either have a single segment + sidx box and use SegmentBase. SegmentList was not tested.
- It is recommended that presentation has a single Period. If has multiple periods, all adaptation sets tructure should be strictly the same in all periods. Changing of media between periods is not supported.
- Encryption is not supported. Widevine CDM and ClearKey CDM are planned for all S805 and S905X units. PlayReady CDM and Verimatrix is planned for special requests.
- Only first available video track (adaptation set) will be selected.
- Any adaptation set filtering is not supported (encrypted can be ignored, however). Audio sets will be signalled one by one.
- Subtitles are not currently supported (WebVTT is planned).
- Represenation set (bandwidth) switching is only possible between video adaptation sets. Audio would always use first representation set signalled.
- In Live mode playlist will be updated more frequently, than it may be needed.
- Any tags controlling buffering or stream priorities are not supported.
Notes and known limitations
- Seeking is not limited to segment boundaries.
- Video tracks can not be switched.
- Switching of audio tracks may sometimes not work.
- When using Flussonic, URL should be «index.m3u8», not «video.m3u8».