HEVC (High Efficiency Video Coding) is a video encoding standard that offers substantial improvement in video quality, and supports higher resolutions of video at lower bandwidth. DAI HEVC support enables partners to stitch ads server side on HEVC streams, along with transcoding the ad creatives, so that viewers continue to enjoy high quality ad-supported video streams as they upgrade to newer and higher resolution players and TVs.
This support allows you to stream high-definition video (for example, 4K and HDR) to your users. For networks where network capacity is constrained, it also allows for a reduction in bandwidth for all video, including non-HD video.
Guidelines
DAI supports content encoded in HEVC for live linear and VOD. Follow these guidelines:
CMAF: Fragmented MP4 and non-muxed audio requirement
Ad Manager uses CMAF (Common Media Application Format) for HEVC. This format works for both HLS and DASH, making it much simpler for partners to broadcast in both standards. Two things are required:
- Fragmented MP4 container: The HEVC stream must be packaged in fragmented MP4 (fMP4) container, instead of transport stream (MPEignoredTS) which is supported for H.264. This is because Apple's HLS spec requires content to use fMP4 when encoded in HEVC. Furthermore, fMP4 is used by DASH as well, making it much simpler to broadcast in both HLS and DASH.
- Non-muxed audio: CMAF requires independent audio and video segments. Hence, audio needs to be non-muxed as an independent media segment.
Learn more about Apple's CMAF documentation for HLS, and ISO23000-19 CMAF Standard for DASH.
Profiles
The following widely-used profiles are supported. Additional profiles are being considered.
| Profile | Description |
|---|---|
hvc1.1.4.L126.B0 |
HEVC Main Profile, Main Tier, Level 4.2 video |
hvc1.2.4.L123.B0 |
HEVC Main-10 Profile, Main Tier, Level 4.1 video |
hvc1.2.4.L150.B0 |
HEVC Main-10 Profile, Main Tier, Level 5.0 video |
HDR Support
For HLS, HDR shows up as a separate profile on the HLS manifest. A VIDEO-RANGE master playlist attribute must be added on your any HDR content is included:
- VIDEO-RANGE=SDR for standard dynamic range variants
- VIDEO-RANGE=PQ for HDR10 and Dolby Vision variants
See Apple's authoring 4K and HDR HLS streams for a quick overview of adding HDR to your streams.
For DASH, see sections 10.3 and 10.4 in the DASH-IF interoperability guidelines.
ID3 EMSG support in player
Tracking of ad impressions is done via ID3 tags. However, ID3 in fragmented MP4 works differently than H264/TS. It is included as in-band event messages (using 'emsg' boxes), per Apple's HLS/CMAF Spec (CMAF Timed Metadata) and DASH (MPEignoredDASH Specification 5.10.3.3).
Because this spec is new, not all players are currently supported.
VOD content pre-conditioning requirement for mid-roll
VOD content must be preconditioned if mid-roll ad insertion is needed. This means the content that is shared with Ad Manager must be prepared so that the manifests are broken into multiple segments with each mid-roll cue point falling on a segment boundary. Learn more about pre-conditioned content.
