Currently most high end phones on the market capture on 1080p at 30 fps.
As we presented on a previous blog post, a number of devices today are adding 4k video capabilities by recording and playing back 2160p at 30 fps. Those include: Acer Liquid S2, Samsung Galaxy Note 3, Sony Xperia Z2, LG G Pro 2, Samsung Galaxy S5.
This is due to the fact that the latest high-end SOCs from Qualcomm (Snapdragon 800 and 801) incorporate a H.264/AVC 4K capable encoder and these devices are becoming widely available.
Nevertheless, the current bit rates needed to record 4K are very high, in the range of 50 mbps (400 Mbytes per minute), this is very difficult to accommodate in the flash capacities used on current devices and leads to the situation where most of the announced devices actually record on 1080p at 30 fps by default, using in the range of 20 mbps to do so, still high but more manageable.
In addition not every device is using the same encoder or configuration, we do have some examples here:
In addition we have seen demonstrations of 4K H.264/AVC decoding with Nvidia Tegra 4 and K1 and Mediatek MT6595 and of HEVC/H.265 4K decoding with Qualcomm Snapdragon 805 and Mediatek MT6595. Samsung (Exinos 5422) and Nvidia (Tegra 4 and K1) have announced to be able to provide 4K video encoding using H.264/AVC and Mediatek (MT6595) have announced 4K recording with HEVC/H.265, but we have not seeing any demonstration or product using these capabilities yet.
Dedicated video recorders like GoPro or Sony HDR-AS1X require much lower bit rates when recording on 1080p at 30 fps, needing only in the range of 15 mbps using H.264/AVC and arguably with better video quality and lower bit rate are used on broadcasting encoder products.
Some fundamental conclusions:
4K is becoming available in many high end smart phones.
Current bit rates used are too high to use this feature widely.
Current video encoders used on mobiles SOCs are not as efficient as start of the art video encoders used on other products.
Two components are needed to make 4K widely used on mobile devices:
HEVC encoder support
A HEVC encoder that is actually as efficient as the standard allows
At NGCodec we are working against that target and we are working on an video encoder that delivers 4K video at todays 1080p bit rates and with realistic power consumption, cost and size.