For best quality results, H264 Hardware Decoding on or off?

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copycat29
Posts: 75
Joined: Sat Oct 17, 2009 10:36 pm

For best quality results, H264 Hardware Decoding on or off?

Post by copycat29 »

Hello.

I have read user comments here that suggest the use of the H264 Hardware Decoding options in ConvertXtoHD can speed up
encoding times but will give less quality results than letting the program use your CPU only for the encoding.

Is this true that enabling the H264 Hardware Decoding options will give less quality results than CPU only?

Does enabling these options mean the program is using both the CPU and GFX card for the encoding?

I would really like it if I could speed up my encoding times especially since encoding a 1080p Blu-ray can still take some hours to
complete even on my Intel i7 5960X depending on the source file and these options being enabled could reduce my encoding
times by quite a bit, thought I don't want to use these options if the final quality result it noticeably less than it would when
letting the program use the CPU only.

The bottom line is if I want to maintain the absolutely best quality results, should I use H264 Hardware Decoding or not?

Thank you in advance for the feedback.
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cedric
VSO Team Member
Posts: 1375
Joined: Fri May 02, 2008 9:31 am
Location: Toulouse-FRANCE

Re: For best quality results, H264 Hardware Decoding on or o

Post by cedric »

Hello,

Hardware DECODER option will not change the video quality, but can decrease encoding speed in some cases (if CPU is able to decode video faster than GPU, your case I think)

Hardware ENCODER option will reduce the video quality because some fine tuning settings are not available.
If your CPU is able to convert with good speed, you don't need to enable hardware encoding.
Hardware encoding is only useful when using a slow computer.

Regards,
copycat29
Posts: 75
Joined: Sat Oct 17, 2009 10:36 pm

Re: For best quality results, H264 Hardware Decoding on or o

Post by copycat29 »

Thanks for getting back to me. I guess I am best not using H264 Hardware Decoding then
if I would like to maintain the absolute best encoding quality out of the program.

I tend to convert a lot of those HDTV 1080i ts type files to 1080p Blu-ray to fit on a
BD 25 disc and even on my Intel i7 5960X, it takes 3 to 7 hours to encode.

The settings I use is resize filter Lanczos and Two pass encoding as well
as setting the other options for best encoding quality.

I see ConvertXtoHD brings even my Intel i7 5960X to its knees when using the Two pass
encoding option which is what I always use. The first pass is quite quick but the second
pass puts most of the time on the encoding and slows the encoding right down and uses
100% of the CPU which means you can't really do anything on the computer while it is
encoding because windows is very sluggish and takes some seconds to respond.
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