This is a 1st-gen chip with H.264 and VP9 support. Apparently, they've already got early versions of the next generation with AV1 which will hopefully mean wider adoption of AV1 will be coming in the next few years.
AV1 is already here. Lots of YouTube videos have AV1 encodes and they'll playback in software on your desktop as long as your browser supports AV1. You can see which codec you're using by right clicking on the video and selecting the "Stats for nerds" menu item.
I was most curious about how they parallelise the encoding for the multiple resolutions. The juicy bits from the paper are [1]
"MOT [multiple-output transcoding] is an alternative approach where a single transcoding task
produces the desired combination of resolutions and formats for
a given chunk (Figure 2b). The input chunk is read and decoded
once, and then downscaled and encoded to all output variants in
parallel. This reduces the decoding overheads and allows efficient
sharing of control parameters obtained by analysis of the source
(e.g., detection of fades/flashes). MOT is generally preferred to SOT,
as it avoids redundant decodes for the same group of outputs, but
SOT may be used when memory or latency needs mandate it."
"Multiple-output transcoding (MOT) was considered foundational
for encoder utilization because of the benefits discussed in Section 2.
The efficiency of decoding once, scaling, and encoding an entire
MOT graph on a single VCU simplifies scheduling and reduces
resource consumption at the data center level. The typical structure
of a multi-output transcode is a single-decode and then the set of
conventional 16:9 outputs (e.g. for 1080p inputs: 1080p, 720p, 480p,
360p, 240p, and 144p are encoded). This scales down the decode
needs of the VCU by the number of outputs and generally only
doubles the encoding requirements. Few videos require an entire
VCU for their MOT, so we designed our VCUs to perform multiple
MOTs and SOTs in parallel to boost encoder and VCU utilization"
"In fact, our production workload is largely MOT, which was
not supported on our GPU baseline. Prior to VCU, the production
workload used multiple SOTs instead of running MOT on CPU
given the high latency. MOT throughput is 1.2-1.3x higher than
SOT (976 Mpix/s on H.264 and 927 Mpix/s on VP9), stemming from
the single decode that is reused to produce all the output resolutions."
I grabbed the list of formats for a current popular video too [0] just to give me an idea.
3 comments
[ 2.2 ms ] story [ 21.5 ms ] thread"MOT [multiple-output transcoding] is an alternative approach where a single transcoding task produces the desired combination of resolutions and formats for a given chunk (Figure 2b). The input chunk is read and decoded once, and then downscaled and encoded to all output variants in parallel. This reduces the decoding overheads and allows efficient sharing of control parameters obtained by analysis of the source (e.g., detection of fades/flashes). MOT is generally preferred to SOT, as it avoids redundant decodes for the same group of outputs, but SOT may be used when memory or latency needs mandate it."
"Multiple-output transcoding (MOT) was considered foundational for encoder utilization because of the benefits discussed in Section 2. The efficiency of decoding once, scaling, and encoding an entire MOT graph on a single VCU simplifies scheduling and reduces resource consumption at the data center level. The typical structure of a multi-output transcode is a single-decode and then the set of conventional 16:9 outputs (e.g. for 1080p inputs: 1080p, 720p, 480p, 360p, 240p, and 144p are encoded). This scales down the decode needs of the VCU by the number of outputs and generally only doubles the encoding requirements. Few videos require an entire VCU for their MOT, so we designed our VCUs to perform multiple MOTs and SOTs in parallel to boost encoder and VCU utilization"
"In fact, our production workload is largely MOT, which was not supported on our GPU baseline. Prior to VCU, the production workload used multiple SOTs instead of running MOT on CPU given the high latency. MOT throughput is 1.2-1.3x higher than SOT (976 Mpix/s on H.264 and 927 Mpix/s on VP9), stemming from the single decode that is reused to produce all the output resolutions."
I grabbed the list of formats for a current popular video too [0] just to give me an idea.
[0] https://www.youtube.com/watch?v=ehv3zQAa9zM [1]A showcase of shard-db. Data from the Hacker News API. Refreshed every 15 minutes.
Source · Live DB stats