8.13a Produces Videos that VLC Won't Play - Fixed in 815a

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Danr

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Regarding MPEG2 to HEVC file szies. If you're doing forced recode, then I recommend using the CRF mode for best results. It works well with all the encoders and is faster than 2 pass encoding.

If you're doing intelligent recode from MEPG2 to HEVC then I would suggest setting the quality factor around 25% to 30%. This basically says that if the source and destination are the same dimensions then the HEVC output will be 25% of the size of the original MPEG2. BTW, this only refers to the video data. Audio data could be smaller, same or larger depending on which codec and bit rates you're using.
 

jgrassi

Member
Oh wow, I'm a believer! I made two videos from MPEG source. One like I always do creating an MP4 file with H264 codec using stock ipad 720 profile. That file is 820K. Next made MKV file using HEVC codec using DanR's suggestions with quality at 25%, forced recode, and CRF mode with slider at 23. Resulting MKV file was only 320K and I actually can't tell the difference in quality! Attached are two screen grabs of a fairly detailed shot in the video. Look identical to me. So looks like I have a great way to reduce my file sizes without sacrificing quality. Thanks Dartman for getting me to try other modes and thanks Danr for the great suggestions for creating smaller / same quality videos,From 300K MKV file.jpgFrom 800K MP4 file.jpg
 

Dartman

Member
Hows the motion blur and smoothness, that looks fine on a still shot. Thanks for trying my ideas and helping to give us new ideas to try from there.
 

jgrassi

Member
When both are playing side by side using two VLC windows, I can't tell the difference during action shots. Both look great / smooth to my eyes!
 

Dartman

Member
I probably need to give that a shot. I already recoded all my saved videos to my hevc settings and saved about half of the space on my mostly full external drives. I'll have to do some at different settings as I was happy enough with what I had but if it looks the same all around more space is better.
 

Danr

Administrator
Staff member
Oh wow, I'm a believer! I made two videos from MPEG source. One like I always do creating an MP4 file with H264 codec using stock ipad 720 profile. That file is 820K. Next made MKV file using HEVC codec using DanR's suggestions with quality at 25%, forced recode, and CRF mode with slider at 23. Resulting MKV file was only 320K and I actually can't tell the difference in quality! Attached are two screen grabs of a fairly detailed shot in the video. Look identical to me. So looks like I have a
The quality factor is only used with intelligent recode and is ignored in forced recode. When intelligent recode requires a recode it uses the quality factor as part of the bit rate output bit rate calculation

Also, If you're using NVEnc (and I believe QSync too), you're going to force deinterlacing. Unless you use a BOB deinterlace at twice the frame rate and half the frame size, you're going to have some picture loss converting to progressive. That's just the nature of deinterlacing.
 

jgrassi

Member
Once again, thanks for the education. This post has been very enlightening. Love my new smaller size TV shows...
 

jgrassi

Member
So since I prefer MP4 files (VLC displays subtitles with MP4 files but not MKV files), I took a standard MP4 profile and did nothing but change the codec to HEVC. VRD immediately stops with an FFmpeg error.

Error.jpg

The log states:
FFmpeg (Error) - Could not find tag for codec hevc in stream #0, codec not currently supported in container
Output graph aborted at module: Output muxer, error: FFmpeg muxer: error writing file header.

Is using the HEVC codec not allowed to create the MP4 file container? I assumed this was a valid processing approach since there is an HEVC choice in the MP4 profile codec pulldown menu. I tried looking in the application notes, but couldn't find what containers the HEVC codec supports. Thanks.
 

Dartman

Member
What hardware are you trying to use for the default recoding engine. On my windows 7 box I have a old Nvidia GT640. It is allowed to be used for the hardware engine BUT it doesn't support the HEVC codec, it does support h264. So I was trying to use my 7 box to recode in HEVC and it didn't warn me it can't do it, it just threw up a similar error and quit. If I set it to h264 it worked very fast with the i7980 in that's box. It would also though try to recode HEVC very slowly if I set the engine to software. Admittedly I am using HEVC but I'm not using mp4 so I spose it's possible it just doesn't support being in a HEVC container.
 

jgrassi

Member
Hi, using Win 10 on i7 8700 with Nvidia GTX 1060 so I am able to use Nvenc vice software encoding . I do whatever it takes to make sure Nvenc is used since the reduction in processing time is dramatic. So if HEVC won't work I use H264 which always works with mp4. Like I said, I prefer mp4 since VLC displays subtitles on mp4 files but nothing else I have tried. So right now using Nvenc / H264 / Mp4 with CRF encoding. Love the results, but was curious why HEVC doesn't work since it IS selectable in the dropdown in the profile. Was hoping one of the Dan's would respond via this forum to see if it is a bug or just not supported. Thanks for weighing in.
 

Danr

Administrator
Staff member
No problem creating an HEVC MP4 with NVEnc here. I'm using a GTX 1050. Using build 815a.
 

Danr

Administrator
Staff member
The other thing to test, is to output as an MKV, as that works, and then remux the MKV to MP4.
 

jgrassi

Member
Sent log for error that occurs from directly creating HEVC MP4 file. Will try your suggestion next.

UPDATE - Tried you suggestion and it STILL FAILS going from MKV to MP4 when HEVC is selected.
 

Danr

Administrator
Staff member
Send me the MKV file and I'll try it here. Also upload the log to us. Sending the log file from within VRD isn't working right now.
 

Danr

Administrator
Staff member
The problem is that you started with an ipod profile and modified the codec from h264 to hevc. The ipod profile has an mp4 setting that doesn't support hevc. Click on the advanced button and change the "MP4 mux format" to Generic from ipod. That should work.
 

jgrassi

Member
Ok thanks, I didn't think it mattered. I was used to using that profile from years ago, and just kept using it as a matter of routine. I will try your suggestion. So going directly to the MP4 profile and modifying that for audio adjustments and quality is the right way I am assuming...

Yea, it worked! Thanks again for the education. I actually have been using that ipod profile since version 3! "Most" of the time, my bug reports are valid...
 
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