LAV Filters - DirectShow Media Splitter and Decoders

[Thunderbolt8]

hm is this a specialty of AC3, compared to DTS? because e.g. in DTS master suite theres only 1 configuration for 5.1 tracks (Ls, Rs)

[nevcairiel]

Both Dolby and DTS define a whole list of speaker positions and their naming.

These are the DTS names for channels, and their speaker position according to the DTS specification (degrees relative to your nose when looking at the screen)
Ls/Rs: Left/Right surround, 110 degrees
Lsr/Rsr: Left/Right surround rear, 150 degrees
Lss/Rss: Left/Right surround side, 90 degrees
Lw/Rw: Left/Right wide, 60 degrees

Typically, in 5.1 you'll find Ls/Rs being used (thats what the "side" layout in FFmpeg uses, its named after the WAVE specification which uses plain rear and side names), in older formats the Lsr/Rsr are used sometimes (thats the plain 5.1 in ffmpeg).
In 7.1, its typically both Ls/Rs and Lsr/Rsr, but that can vary.

Dolby defines the channel similarly, but not necessarily with equal angles etc.

[Thunderbolt8]

so the (side) Ls/Rs setup is the common one nowadays? and so the track is not a rather a-typical one? would it sound strange if your setup is rather rear/behind when you play this "side" track or would it sound as it is supposed to be?

[huhn]

if you want it to sound as it is intended you theoretical need to change the speaker setup in that case.

with bit streaming your AVR my even be remixing to move them ever so slightly if it knows your speaker position.

i suggest you to just ignore it. it's a spec that is hard to follow.
maybe there are now audio renderer where you can specify your setup but i don't know that.

even if your setup is "incorrect" it will not sound terrible.

[tebasuna51]

Standard channel layouts:
...
5.1            FL+FR+FC+LFE+BL+BR  standard in XX Century (decoded from Ls-Rs in AC3,DTS,...)
5.1(side)      FL+FR+FC+LFE+SL+SR  standard in XXI Century (decoded from Ls-Rs in AC3,DTS,...)
...

Read also https://mediaarea.net/AudioChannelLayout to understand different names for channels

An AVR 5.1 send to Surround speakers (Ls-Rs 110-120º) both channels SL-SR 90º (Lss-Rss) and BL-BR 150º (Lb-Rb)

[flossy_cake]

In LAV Video if I set Deinterlacing Mode to Auto, does this mean my selected Software deinterlacer will only be activated if the stream has interlace flags? And is this 100% reliable in terms of avoiding false positives -- i.e could some progressive sources be accidentally detected as interlaced and therefore have software deinterlacing applied to them which would needlessly degrade the progressive image?

[el Filou]

Yes; and no.
As the tooltip says, 'Auto' uses frame flags to decide.
If a progressive stream is incorrectly flagged as interlaced frames, it will be passed through the chosen software deinterlacer.

[flossy_cake]

Thanks.

Sorry if this is a silly question but is there an arg I can pass to LAV Splitter to tell it to select a particular subtitle track? I know I can pass it eg. "eng" to select the English track, but I have multiple English tracks, eg. track 2 is an English commentary track. Is there some arg I can pass to tell it "track 2"?

I have read the readme here but it doesn't seem to cover such a scenario.

In case you're wondering why don't I just use MPC-HC's built in subtitle selector or LAV Splitter's tray icon...the answer is that I'm calling LAV Splitter from Avisynth via DSS2() and I am trying to pass it arguments for subtitle track selection so that I don't have to manually set it every time I open the .avs file.

edit: code sample

video = dss2(sourcefile, subsm=2, lavs="l3 vc2 sm3 sl[] sa[eng] es0 ti1", lavf_path="C:\Program Files (x86)\K-Lite Codec Pack\Filters\LAV64")

audio = directshowsource(sourcefile, video=false, audio=true)

AudioDub(video, audio)

[Sunspark]

The only way I know of is via using the @ operator.

eng@SDH eng@ass both work.. I don't have commentary tracks so I can't see how they're labelled on your side, but eng@commentary or whatever is in the square brackets should work.

[flossy_cake]

Originally Posted by Sunspark

The only way I know of is via using the @ operator.

eng@SDH eng@ass both work.. I don't have commentary tracks so I can't see how they're labelled on your side, but eng@commentary or whatever is in the square brackets should work.

Thank you, it works:

[flossy_cake]

I was wondering about how LAV Video handles the "repeat flags" for "soft telecined" NTSC DVD MPEG2 streams.

From what I can tell the MPEG2 stream on the disc is stored as 24p but contains some "repeat flags" to tell the player when to repeat frames/fields to make it come out as 60hz 3:2 pattern.

This makes sense but how does LAV handle it exactly -- is it creating repeat FIELDS or FRAMES? Does it assume 60hz in its calculation for repeating these fields/frames?

I noticed when playing such material on 120hz display, I still have 3:2 judder even though 24 goes 5:5 into 120. From this I'm inferring that LAV Decoder must be assuming the repeat flags are intended for 60hz display -- is that codified in the MPEG2 spec or does LAV make the decision about the timing of the repeat flags?

edit: after some more testing it seems LAV uses the repeat flags to convert it to 60p. The LAV settings GUI doesn't seem to offer an option to not perform this conversion and just output it as 24p.

edit: a 60i option would be nice too as there are some edge cases where that can be beneficial.

[nevcairiel]

LAV does not repeat fields on its own. It forwards the metadata to the renderer, which can decide to repeat frames, or not to.

[huhn]

as far as i know the Microsoft decoder is outputting soft telecine as hard telecine and the lav is not so you have to disable the Microsoft decoder to get soft telecine.
and if i remember correctly the microsoft decoder is used by default when a normal dvd is loaded to make menus work.

[nevcairiel]

LAV Filters 0.77

LAV Splitter
- Fixed: Improved handling of multichannel PCM channel assignments
- Fixed: MP4 Keyframe information could be wrong

LAV Audio
- NEW: Support for audio with more then 8 channel, including automatic downmixing if required

Download: Installer (both x86/x64) -- Zips: 32-bit & 64-bit

Nothing much to say for this one. Lots of under-the-hood changes in FFmpeg, bugfixes, speedups, etc. dav1d was updated for faster AV1 decoding.

Thats it. Short and sweet.

[Manni]

Thanks for all your work

[ryrynz]

Stellar as always.

[SeeMoreDigital]

I wonder if someone can help...

I've managed to configure LAV Filters to parse every audio format with MPC-BE 1.6.4. except LPCM.wav files!

What do I need to do?

[chros]

Thanks Nev!

[tebasuna51]

Originally Posted by nevcairiel

LAV Filters 0.77
[CODE]
LAV Splitter
- Fixed: Improved handling of multichannel PCM channel assignments
...

Many thanks!

[AYColumbia]

Thanks very much.