Source: MPEG2 1920x1080/60i 25Mbps
Target 1: H.264 MP4, 1920x1080/30p 16Mbps (Default PD profile, avg video bitrate 15.5Mbps)
Target 2: H.264 MP4, 1920x1080/30p 4Mbps avg video bitrate custom profile based on Target 1
The table below lists [encode ratio, filesize(MB) , Produced video bitrate (Mbps)]
encode ratio=timeline duration/encode time so the higher the better. A ratio of 10 would mean one can encode a 10min timeline duration in 1 minute.
GPU | PD15 Target 1 | PD14 Target 1 | PD15 Target 2 | PD14 Target 2 |
GTX1070, 372.90 | 10.0 , 1166 , 15.5 | 10.0 , 1166 , 15.5 | 10.0 , 324 , 4.0 | 10.5 , 324 , 4.0 |
R9 380, 16.7.3 | 3.50 , 238 , 2.8 | 3.5 , 238 , 2.8 | 3.5 , 95 , 1.0 | 3.5 , 95 , 1.0 |
As noted in results above, one can see the massive shortcoming between defined avg video bitrate of the produced profile and what the encoder produced for the R9 380 GPU as I noted earlier. The GTX1070 results provided profile intent avg bitrates which obviously is also reflected in produced file size.
GPU encode performance is also a function of overall computer capability so results may vary even if one has the same GPU.
Jeff