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Converting HEVC - Max bitrate 32k?

Posted: 14 Apr 2024 01:27
by lemming3k
I'm trying to convert a HEVC codec to MP4 as it won't play in native windows apps. I've managed this a few times in the past without issues and looking through instructions I seem to be doing everything the same way - but for some reason this one isn't converting.

If I use the H.264/265 convert/save presets and keep original video it either comes out exactly the same as the original, or reduces to 700mb and an awful quality - which I think is based on the greyed out bitrate being just 800.
When I untick the keep original video and manually set the bitrate it sometimes comes out but still greatly compressed as it seems the max bitrate is 32k? Is that correct? The original file is over 40k.

I feel like I'm missing something obvious here, but can't work out what. Has something changed in a recent VLC update? Is there a factory reset option in case I've messed up any settings? If not could anyone recommend another program?

Re: Converting HEVC - Max bitrate 32k?

Posted: 15 Apr 2024 12:43
by Lotesdelere
I'm not sure what you're asking for.
First, MP4 is not a format but a container. It can contains HEVC video streams, H.264/AVC video streams and many more. I guess you're trying to convert to H.264.
Then, the bitrate highly depends on the complexity of the source images. 32k and 40k ? Are we talking about video ? The unit usually used for the bitrate is kb/s, so we are usually talking about bitrates like 1500 kb/s or 5000 kb/s, etc.
The best thing to do is not to force a specific constant bitrate but to use CRF as I've explained there:
https://forum.videolan.org/viewtopic.php?f=14&t=158610
https://forum.videolan.org/viewtopic.php?f=2&t=158117

Re: Converting HEVC - Max bitrate 32k?

Posted: 15 Apr 2024 21:11
by lemming3k
I'm not sure what you're asking for.
First, MP4 is not a format but a container. It can contains HEVC video streams, H.264/AVC video streams and many more. I guess you're trying to convert to H.264.
Then, the bitrate highly depends on the complexity of the source images. 32k and 40k ? Are we talking about video ? The unit usually used for the bitrate is kb/s, so we are usually talking about bitrates like 1500 kb/s or 5000 kb/s, etc.
The best thing to do is not to force a specific constant bitrate but to use CRF as I've explained there:
https://forum.videolan.org/viewtopic.php?f=14&t=158610
https://forum.videolan.org/viewtopic.php?f=2&t=158117
Thank you. As a novice I'm probably not using the right terms.

It's the codec that causes the error and I want to change - ideally with minimal loss (I understand lossless is not possible). So I would assume it is indeed the H.264 profile I want. I'm sure that's the one I've used previously as well. For some reason though it either comes out with a huge loss (something like 95% loss) - or doesn't seem to change the codec as the error remains.

Yes it's the video bitrate. In the original file properties it shows as 43618kbps. It seems that if I manually set this in the H.264 profile settings the max I can go to is 32617(?)kbps. So it's quite significantly lower. I notice sometimes it's greyed out at 800kbps, which is appalling low, and presumably related to the 95% reduction which is just unusable.

I'll try the CRF as suggested and see what happens. Is there a reset profiles option? Just in case I've messed something up somewhere that I need to undo?

Re: Converting HEVC - Max bitrate 32k?

Posted: 16 Apr 2024 12:33
by Lotesdelere
Is there a reset profiles option?

AFAIK the only way is to reset the preferences (the manual way):
https://wiki.videolan.org/VSG:ResetPrefs

Re: Converting HEVC - Max bitrate 32k?

Posted: 16 Apr 2024 18:09
by lemming3k
AFAIK the only way is to reset the preferences (the manual way):
https://wiki.videolan.org/VSG:ResetPrefs
Thanks, I'll give that a go. It doesn't look like the CRF has made a difference unfortunately.

Re: Converting HEVC - Max bitrate 32k?

Posted: 17 Apr 2024 14:18
by lemming3k
Looks like it worked first time in Handbrake using H264 with around 10% loss. None the wiser on why VLC couldn't handle it.