mackworth/cTiVo

low quality video with hevc

Closed this issue · 5 comments

shersoni610 commented

Hello,

I have been experimenting with various bitrate with hevc_videotoolbox. Although
FPS is impressive the video quality is almost garbage. How should I get a good
quality video which is as good as libx265?

Thanks

mackworth commented

Let me connect to @tannebil who's done a lot of work on this issue.

tannebil commented

My experience is that high quality, low bit rate encoding is impossible to achieve with the Apple hardware encoder. Getting quality similar to software encoders requires at least a 30% higher bit rate. The only time I use HW encoding is when the source is a high bit rate MPEG2 and the target is high bit rate H.264/5.

I never found any settings tweak that made a difference. Just kick up the bit rate to 1300+ and take the hit.

I gave up on HW encoding and switched back to “Default”. However, Comcast has switched all my channels to MPEG4 earlier this year so I don’t even bother to transcode shows these days as as smaller size isn’t a priority for me.

The only time HW makes much sense might be if you are running cTiVo on a low-end MacBook Pro and are dealing with MPEG2 shows. A 30% larger show in 25% of the time is an attractive trade.

mackworth commented

for more details, you can see issue #343 . Let me know if I can do anything else for you.

mackworth commented

FYI, it looks like Handbrake is now doing a decent job on this. Here's a couple of Formats to Import and try:
HB HW Formats

mackworth commented

Note revised version:
HB HW Formats