The State of MPEG-DASH Deployment

People have been recently discussing some of the points raised by this article at Streaming Media Website, it’s worth a read. A few of the points from the article worth noting;

LTE Broadcast and Pay TV.

• With LTE Broadcast the device can switch on the fly from a unicast DASH session to a multicast DASH session. 
• This broadcast/multicast DASH session only has one variant stream. 
• On congested cells it provides a mechanism to deliver content to more users. 
• Could CC leverage this ability in some way?

• Netflix a bit like YouTube don’t use the DASH standardised MPD (Media Presentation Description) to detail all available variants, which means they aren’t really DASH, in my opinion. They use one the file formats specified in Dash, a variant of MP4 file format. This is a trend we have seen content providers follow, choosing parts of the standard they like and not others. 
• Netflix and YouTube are using CENC (Common Encryption) standard as supported by DASH to DRM their content. This provides the ability to switch to different DRM providers and not to be tied to one specific version. 
• HbbTV (Hybrid Broadcast Broadband TV) TV sets are reported to becoming available to consumers. The latest version of the HbbTV specification supports DASH only formatted content for DRM protected content.

Further Reading
Multicast-broadcast single-frequency network http://en.wikipedia.org/wiki/Multicast-broadcast_single-frequency_network




Ericsson LTE Broadcast http://www.ericsson.com/ourportfolio/telecom-operators/lte-broadcast

CENC http://docs.unified-streaming.com/documentation/protect/common-encryption.html

HbbTV https://www.hbbtv.org/

H.265 Presets

x265 has a number of predefined --preset options that make trade-offs between encode speed (encoded frames per second) and compression efficiency (quality per bit in the bitstream). The default preset is medium, it does a reasonably good job of finding the best possible quality without spending enormous CPU cycles looking for the absolute most efficient way to achieve that quality. As you go higher than medium, the encoder takes shortcuts to improve performance at the expense of quality and compression efficiency. As you go lower than medium, the encoder tries harder and harder to achieve the best quailty per bit compression ratio.

The presets adjust encoder parameters to affect these trade-offs.

	ultrafast	superfast	veryfast	faster	fast	medium	slow	slower	veryslow	placebo
ctu	32	32	32	64	64	64	64	64	64	64
bframes	4	4	4	4	4	4	4	8	8	8
b-adapt	0	0	0	0	2	2	2	2	2	2
rc-lookahead	10	10	15	15	15	20	25	30	40	60
scenecut	0	40	40	40	40	40	40	40	40	40
refs	1	1	1	1	3	3	3	3	5	5
me	dia	hex	hex	hex	hex	hex	star	star	star	star
merange	25	44	57	57	57	57	57	57	57	92
subme	0	1	1	2	2	2	3	3	4	5
rect	0	0	0	0	0	0	1	1	1	1
amp	0	0	0	0	0	0	0	1	1	1
max-merge	2	2	2	2	2	2	3	3	4	5
early-skip	1	1	1	1	0	0	0	0	0	0
fast-intra	1	1	1	1	1	0	0	0	0	0
fast-cbf	1	1	1	1	0	0	0	0	0	0
sao	0	1	1	1	1	1	1	1	1	1
signhide	0	1	1	1	1	1	1	1	1	1
weightp	0	0	1	1	1	1	1	1	1	1
aq-mode	0	0	2	2	2	2	2	2	2	2
cuTree	0	0	0	0	1	1	1	1	1	1
rdLevel	2	2	2	2	2	3	4	6	6	6
lft	0	1	1	1	1	1	1	1	1	1
tu-intra	1	1	1	1	1	1	1	2	3	4
tu-inter	1	1	1	1	1	1	1	2	3	4

Placebo mode further enables transform-skip prediction analysis (lossless).

–tune	effect
psnr	disables adaptive quant, psy-rd, and cutree
ssim	enables adaptive quant auto-mode, disables psy-rd
fastdecode	no loop filters, no weighted pred, no intra in B
zerolatency	no lookahead, no B frames, no cutree