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Old 7th June 2022, 19:29   #24801  |  Link
VipZ
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Cool, thanks
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Old 10th June 2022, 12:04   #24802  |  Link
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I have tried with a simple search but had no results.

Can LAV Filters play AC-4?
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Old 10th June 2022, 22:19   #24803  |  Link
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No because it's not supported yet in ffmpeg's open source decoders.
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Old 11th June 2022, 09:27   #24804  |  Link
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Quote:
Originally Posted by el Filou View Post
No because it's not supported yet in ffmpeg's open source decoders.
It seems that some support is there.

There are Kodi builds working with AC-4 already.
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Old 11th June 2022, 09:40   #24805  |  Link
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That is all illegal, beware of getting sued by Dolby.
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Old 11th June 2022, 12:07   #24806  |  Link
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welcome to doom9 THE in-place of illegal DVD conversation.
we even have a decryption sub forum.

so what do i miss here is none opensource code direcly shared from dolby or something?
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Old 12th June 2022, 07:48   #24807  |  Link
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so what do i miss here is none opensource code direcly shared from dolby or something?
Dolby has a Github repository with source code for its plugins.
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Old 12th June 2022, 09:59   #24808  |  Link
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THen just use their plugins an be happy user.
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Old 12th June 2022, 22:57   #24809  |  Link
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For LAV Splitter "Advanced" drop-down, I had to re-write the subtitle selector string because MPC-HC wasn't picking the right ones up with the old one I was using.

Sharing it here in case anyone wants it and uses English subtitles all the time as I do. The order of selection is left-to-right.

You can also set an audio language preference as well, but better to select the audio track manually depending on what you're watching.

eng@SDH eng|h eng@ass eng|n *|d

eng@SDH - All audio languages, use english subtitles for deaf&hearing impaired.
eng|h - Same as above, I don't recall seeing the hearing impaired flag in use, but including it anyway just in case, possibility it won't work in which case change to *|h if I encounter it.
eng@ass - Needed for a Japanese file that contained both ASS and PGS format subtitles in English with ASS being the preferred one.
eng|n - Needed for some files that have a default,forced english subtitle track that surprisingly contains no subs at all, this will select the English one with subs.
*|d - Needed for a Japanese file that has English subtitles, but won't select it with any of the above rules. eng|d did not work, needed to be *|d to work.

In regard to the SDH subtitle track, it's true it is sometimes unnecessary to see descriptions of sounds e.g. [papers rustling] and perhaps especially descriptions of the music, e.g. [despairing music] or whatever, it is needed because sometimes during a sequence where music is playing, this is the track that will contain the lyrics to the song that is being played (if present). The normal track does not contain song lyrics.
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Old 13th June 2022, 07:25   #24810  |  Link
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Where did you find that "lang@something" syntax? It's not documented in the readme file.
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Old 13th June 2022, 08:57   #24811  |  Link
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The @ character isn't documented, I saw it on a forum, but it does work. You can use it to match a word in the list of subtitle tracks. Very useful functionality.

Nevcariel: I found a performance issue. One file I have is one of those weird HEVC main 10 anime files. I have observed on my system comparing the stats with dxva2 copy-back vs software decoding, the cpu usage is the same for both, however with software decoding for this file the gpu load is identified as 8% vs 24% using dxva2 copy-back. The stats identify dxva2-cb as being active. This is a 3x difference in gpu load. If one uses software chroma/image scaling instead of dxva, then the differential is even greater. Do you know why the hardware decoder is so much worse than the software one in this example?
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Old 13th June 2022, 09:46   #24812  |  Link
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I suspect that the problem is in your system, not LAV.
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Old 13th June 2022, 16:39   #24813  |  Link
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Quote:
Originally Posted by Sunspark View Post
I have observed on my system comparing the stats with dxva2 copy-back vs software decoding, the cpu usage is the same for both, however with software decoding for this file the gpu load is identified as 8% vs 24% using dxva2 copy-back. If one uses software chroma/image scaling instead of dxva, then the differential is even greater.
What GPU and renderer on what system?
DXVA copyback has inefficiencies: https://forum.doom9.org/showthread.php?t=176642
It's possible the time the GPU has to wait for the decoded frames to be transfered over the bus and back is counted as GPU active usage time, it depends on how the GPU driver decides to report this.
I find it very weird that decoding 10-bit H.265 would give the same CPU usage when using software and GPU decoding.
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so what do i miss here is none opensource code direcly shared from dolby or something?
richardpl is the author of that AC-4 code in his own ffmpeg fork that has reportedly been used in Kodi builds and other stuff and the licence is GPL. It's dated from 15 months ago but it hasn't been upstreamed into the main ffmpeg code, so maybe there's a legal problem?
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Old 13th June 2022, 18:59   #24814  |  Link
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I did some more testing.. there is an issue and it's partially CPU-related.

My CPU is a Broadwell, iGPU HD 6000.

"Broadwell will be implementing a hybrid H.265 decoder, allowing Broadwell to decode the next-generation video codec in hardware, but not with the same degree of power efficiency as H.264 today. In this hybrid setup Intel will be utilizing both portions of their fixed function video decoder and executing decoding steps on their shaders in order to offer complete H.265 decoding. The use of the shaders for part of the decoding process is less power efficient than doing everything in fixed function hardware but itís better than the even less optimal CPU."

As currently implemented on Broadwell, using copy-back or software on HEVC will have the same CPU load, but GPU load is much lower with software decoding. Native does not have a lower GPU load, but does have a little lower CPU load. Using D3D11 does not change anything.

LAV work-around: uncheck HEVC in the list of codecs for HW decoding to ensure that HEVC is always software-decoded.

I tested MPC-BE's video decoder and left HEVC checked, no difference with the load issue. It's not the video renderer, because just now I was testing with mpcvr, and last night it was with madvr.

I wonder why using software decoding is better than hardware decoding? Could it be that Intel has done something where if it's software-decoded it actually does perform some invisible hardware acceleration to reduce the GPU load, but when it's using one of the hardware decoding codecs used by LAV, etc. it goes through a non-optimal path instead?
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Old 13th June 2022, 19:34   #24815  |  Link
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well you said it is a hybrid decoder which means it's as usual not that useful or plain bad.

and the GPU is higher in hardware decode here because it is not a asic hardware decoder but a hybrid decoder meaning is is using a lot of actual processing power of the GPU and CPU to do the task.
under certain situations a CPU can be plain better at this.
as you can see they have done a good job in optimising the HEVC software decode in ffmpeg.

what so ever there is no issue.
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Old 13th June 2022, 19:40   #24816  |  Link
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Quote:
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Could it be that Intel has done something where if it's software-decoded it actually does perform some invisible hardware acceleration to reduce the GPU load
LAV uses ffmpeg libraries to decode HEVC in software. I very doubt that Intel drivers hack into ffmpeg libs and alter some code in them.

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I wonder why using software decoding is better than hardware decoding?
It's not hardware, it's hybrid and it suxx.

Last edited by lvqcl; 13th June 2022 at 22:08.
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Old 13th June 2022, 19:55   #24817  |  Link
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The reason software decoding has less GPU load is super simple to understand. It only has to copy the decoded data to the GPU once.

With copyback, the data first geta copied to GPU in compressed form, then copied back in uncompressed form, and then copied to GPU again.

Hybrid decoding of Broadwell is crap.
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Old 13th June 2022, 20:16   #24818  |  Link
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I just found it odd the results, I was under the impression that using DXVA2-Native or D3D11-Automatic would have better results with HEVC due to reduced traffic, but it only had a bit of CPU reduction and no reduction for GPU.

I accept that the situation for this CPU isn't going to change for this media type.

FFMPEG folks have done an impressive job.
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Old 24th June 2022, 16:45   #24819  |  Link
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Noob question: with LAV video decoder already using dithering, is it better to disable dithering in video renderers (madVR / MPC VR)? Or do they apply to different things?
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Old 24th June 2022, 17:58   #24820  |  Link
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Noob question: with LAV video decoder already using dithering, is it better to disable dithering in video renderers (madVR / MPC VR)? Or do they apply to different things?
Different things. If the renderer has support for stuff like dithering, levels, etc. those are passed through and it is the renderer on the other end that sets the settings.

Those settings won't change anything with those two renderers. If you need to change dithering, levels, etc. in MadVR or MPCVR you have to do it on that side.
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