Many major online content publishers are using a combination of both HLS and MPEG-DASH to reach their audience across all platforms and devices. Although effective, this also complicates their encoding, DRM and deployment workflow. Apple and Microsoft are looking to ease this burden with the introduction of the Common Media Application Format (CMAF) standard.
Where HLS uses the Transport Stream (TS) container format for packaging its media, MPEG-DASH is almost solely used in combination with fragmented MP4 (fMP4). Content publishers utilizing both formats currently need to pay twice to encode and store their content. Furthermore, these files, although representing the same media, will both be competing for space on CDN edges, reducing the overall delivery efficiency.
5 Advantages of CMAF for Content Publishers
1. Support for both MPEG-DASH and HLS
Where HLS is typically delivered with Transport Stream containers and MPEG-DASH with fragmented MP4 (fMP4), CMAF specifies an fMP4 compatible container format.
Utilizing this fMP4 container, will allow content publishers to encode and store their media once and deliver it with both the HLS and MPEG-DASH segmented adaptive streaming protocol, reducing costs and simplifying their overall workflow.
2. It is a more efficient media format
HLS’s Transport Stream (TS) containers are inefficient for segmented adaptive media delivery due to their high overhead and payload ratios in comparison with fragmented MP4 (fMP4). Moving away from TS containers towards fMP4 will increase the effective bandwidth of the stream.
Furthermore, CMAF specifies a low latency streaming mode for cases where latency is of crucial importance and every millisecond counts.
3. It is fully compatible with the Common Encryption (CENC) standard
Without CENC, content distributors have to DRM encode and store their content multiple times, once for each required DRM system. This brings forward a high cost and reduces the overall CDN delivery efficiency.
With CENC, content can be DRM encrypted and stored once and decrypted with a wide range of CENC compatible DRM solutions, such as Google’s Widevine, Microsoft’s PlayReady or Apple’s own FairPlay.
4. It has support for modern and upcoming codecs
Transport Stream containers are designed to carry H.264 and AAC payload. This is furthermore enforced within the HLS specification.
CMAF and its fragmented MP4 container however have support for modern media codecs such as HEVC/H.265 and VP9 as well as for the upcoming Alliance for Open Media Video 1 (AV 1), making them future proof.
5. It has the backing of major industry players
Apple announced to support CMAF in combination with HLS in iOS10, macOS and tvOS. Together with Microsoft’s participation in the CMAF standard, this instils confidence from the industry.
The general expectation is that most browser, operating system and device manufacturers will quickly release updates to their products in order to be compatible with the CMAF standard.
Moving Forward With CMAF
Although the benefits of CMAF are clear, there will still be many legacy devices around that won’t get an update to support CMAF based content playback. At THEOplayer we are confident that CMAF will have a major impact on the streaming industry. We will leverage our knowledge about HLS, MPEG-DASH and fMP4 in order to ensure HTML5-based video playback of CMAF content everywhere, even on older legacy devices and browsers.
The vision for the future is clear. With the addition of CMAF to the HLS protocol, online streaming moves to a strategy of encoding once, packaging once, CENC DRM encrypting once and caching once. Getting started with CMAF is simple, THEOplayer’s HTML5 video player enables content publishers to deliver HLS and MPEG-DASH with CMAF fMP4 to every platform and device while providing a world class viewer experience across the whole line.