LAV vs. ffdshow questions

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LAV vs. ffdshow questions

Post by estevao on Fri May 25, 2012 1:47 am

Hello, I've been using K-Lite CP for years, it's my favorite. During the last 8 months I've been writing a quite large guide to home video "brewing" which started with VirtualDub and VFW/ACM and ended with MeGUI. It's in Brazilian Portuguese and available at http://estevaomonteiro.com/compressaoav.htm . Anyway, I have in the guide a discrete section where I discuss a bit about codec options, where I recommend K-Lite CP with particular attention to LAV and ffdshow. Also an annex listing each pack's contents. In the interest of accuracy, I'd like to ask some questions of you experts. Smile

I understand LAV has been conquering much of ffdshow's previous territory as well as of other codecs such as WavPack. Considering both LAV and ffdshow are ffmpeg-based, my question is: why exactly, in K-Lite's default installation, is LAV considered better than ffdshow for many formats, but not others? Where lies this distinction? I understand LAV is more effective for deinterlacing, DXVA, CUDA and SPDIF. But wouldn't this be true for all formats? Do LAV and ffdshow use the same code from ffmpeg (libavcodec)? I've noted LAV is preffered over ffdshow for video, but the inverse occurs for audio. Is this only because of the installer options such as downmixing? BTW, if I do not use ffdshow downmixing while using a stereo set for a 5.1 video, do I actually lose audio information or the hardware drivers perform the downmixing?

My thanks in advance!


Last edited by estevao on Fri May 25, 2012 1:56 am; edited 1 time in total (Reason for editing : Post title sounded like ranting before.)

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Re: LAV vs. ffdshow questions

Post by Admin on Sat May 26, 2012 2:42 pm

LAV has very good and clean code. It also support almost all formats that are supported by FFmpeg, while ffdshow only uses a subset of its functionality. It is not just relevant that FFmpeg is being used, it also matters how it is used. LAV works very well. For pure video decoding, LAV is certainly the best choice. This is also reflected in the pack's default settings. LAV is used for almost all video formats.

Advantage of ffdshow is that is has various processing filters. But those are usually not used by normal users. ffdshow only has DXVA, it does not support CUDA. SPDIF work good with both in most cases.

ffdshow is still the default for audio because LAV does not yet have channel mixing functionality. But that is high on the ToDo list of its developer. Without a mixer users can have problems like low volume when playing 5.1 audio on a stereo speaker system. In your case your drivers are doing the mixing. Some drivers do it badly and it also depends on the version of Windows. XP has more problems than 7 in that regard.

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Re: LAV vs. ffdshow questions

Post by estevao on Sat May 26, 2012 7:31 pm

Wow, I didn't imagine LAV was even more complete than ffdshow in format support.

Glad to know I seem to have done my homework well and was on the right track. Thanks for the confirmations and details!

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Re: LAV vs. ffdshow questions

Post by Etheroz on Sat Jul 14, 2012 4:27 pm

Admin wrote:ffdshow is still the default for audio because LAV does not yet have channel mixing functionality.

The newest version has support for this, doesn't it? How come ffdshow is still recommended over LAV in the installation?


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Re: LAV vs. ffdshow questions

Post by Admin on Sat Jul 14, 2012 4:40 pm

More options for choosing LAV as audio decoder audio were added.

ffdshow is still default for several reasons:
- It works fine, so no immediate need to switch.
- People are used to it.
- It has more options (such as normalize).
- The new functionality of LAV needs proper testing by large group of people. There already have been several audio related fixes and improvements in the past few days.

Migration from ffdshow to LAV is done very slowly to people can adapt to the changes. Currently LAV is already used by default for all video.

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Re: LAV vs. ffdshow questions

Post by Etheroz on Sat Jul 14, 2012 5:47 pm

Ah, I see. So it's not perfect yet, I guess that's to be expected from a newly implemented feature.


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Re: LAV vs. ffdshow questions

Post by Seldon on Wed Dec 12, 2012 12:38 am

Hi, Guys! I've read this topic, may be LAV have clean code but it absolutely useless for now.
I download new K-Lite pack and be bad surprised.
Jump, Ctrl+Right - one of the necessary function for time economy for passing prompts, advertising and turning boring moments works incorrect.
Than press Ctrl+Right video is freezing on some time ...
if I press Ctrl+Right several times, it does not show video frames and remains frozen. It's cannot be used anyway.
Problem gone when I disable LAV Splitter. (I breathed a sigh of relief)
Clean code of splitter useless fo now.

Second, I use ffdshow Picture properties Contrast and Brightness,
I know where is in ffdshow, where is in LAV?!!!
So I had to return all of the codecs under ffdshow control.

Maybe it does not seem convincing to You,
but what coerce You remove ffdshow preset from install setup?
Please make ffdshow preset in setup, and please support ffdshow
until you have developed the LAV to high level of quality and usability.
Thank You! K-Lite best of the world!

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Re: LAV vs. ffdshow questions

Post by Admin on Wed Dec 12, 2012 5:15 pm

There should be no different in seeking behavior between LAV and ffdshow. Ctrl+right (5 second jump) works fine here with LAV Video decoder. Seeking is almost instantaneous.

I suspect that you might have tested with a file that has slow seeking, due to missing index or large gaps between keyframes. If you have any files where you consistently can reproduce problems with LAV that do not occur with ffdshow, then I would like to have some details about those files.

Picture properties are available in the player and work with any decoder.
MPC options -> Miscellaneous

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Re: LAV vs. ffdshow questions

Post by Seldon on Wed Dec 12, 2012 6:44 pm

Hello, thank You for responding!
Unfortunately everything is more complicated, because ability to quick Seek also depends on CPU / CPUload.
Maybe you have an 8-core Xeon Smile and it have no delay.
Seek - is hard task and of course the problem occurs when processor is overloaded.
I'll try to prepare you an example of video + video snapshot to show problem.
(I'm very busy at work for now, but I will do it later.)

The second question, You can NOT compare four poor picture settings of the player
with a rich of ffdshow settings
(though most of them are rarely used, but it's nice it can quick solve any problem what can be imagine)
besides player setting window is modal, but ffdshow settings can be adjusted on the fly.
You can dynamic try deinterlacing if You have 1080i, or any i-video,
Switch in accuracy deblocking if have old non quality blocking video,
Logoaway - sometimes used, crop than colorized noises on video borders.
You know - ffdshow have many interesting options ... and quick access in one window.
I understand, may be feauture with new good code of LAV, but please do not take away ffdshow and please make one of default install presets for Users who like ffdshow.
Thank You, I will write ...

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Re: LAV vs. ffdshow questions

Post by Admin on Thu Dec 13, 2012 12:03 am

That is why ffdshow is still included. It is there for those who need its additional settings and don't mind its flaws. Its development has pretty much been stopped.
LAV is better, more stable, and gives less problems. That is why that is the default choice.

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