Attract-Mode Support Forum

Attract-Mode Support => General => Topic started by: joyrider3774 on February 23, 2017, 05:06:16 PM

Title: is there any benefit to using libavresmaple over libswresample on the PI 3?
Post by: joyrider3774 on February 23, 2017, 05:06:16 PM

I saw the libavresample option in the makefile so i configured ffmpeg with
"./configure --enable-mmal --disable-debug --enable-memalign-hack --enable-shared --enable-avresample"

and then edited the make file to make sure libavresmaple would be used it compiled fine and everything seems to run fine but can't seem to see / hear any diffrence.

should libavresmaple be faster than libswresample i see the makefile seems to give preference to libswresample but not certain if there is a reason for it or not.

Don't have any video's to test / benchmark with.

I think the choose has an impact on the audio resampler being used just don't know which one is faster in general

anyone can shed some light on this ?

Title: Re: is there any benefit to using libavresmaple over libswresample on the PI 3?
Post by: hermine.potter on February 23, 2017, 11:31:20 PM

@joyrider3774
Here (https://github.com/mickelson/attract/wiki/Compiling-on-the-Raspberry-Pi-%28Raspbian-Jessie%29)
hardware accelerated means that video playback of scraped video files is faster and more stable (without stutter and hanging).
After changing to hardware acceleration, it should works.
Test a scraped video file (e.g. mame).
Then: Start AM > press TAB key > General > Video Decoder : mmal

Title: Re: is there any benefit to using libavresmaple over libswresample on the PI 3?
Post by: joyrider3774 on February 24, 2017, 04:54:24 AM

yes i know that but i'm not talking about mmal decoder for video playback.

I'm talking about libswresample  and libavresample. The make file gives preference over libswresample  if both are available, so i decided to to install libavresample first and then change the makefile so that change libavresample got preference.

I'm not certain when or for what libswresample  or libavresample is even used i'm guessing it has to do with resampling audio. Is it so that if i enable mmal libswresample  and libavresample  are not used ? so it doesn't matter what i compiled it against or does it get used for something (if so what) even when mmal is selected ?

Was just messing about with the sources & compiling them and changing little bits for fun but could not see a diffrence (for one because i was already using mmal and another i have no clue what those 2 libs are used for).

Title: Re: is there any benefit to using libavresmaple over libswresample on the PI 3?
Post by: raygun on February 24, 2017, 09:59:25 PM

I'm not aware of any technical reason why one would be better than the other.  They are both for audio resampling as you figured.  There are two due to the fork that happened to FFmpeg a few years ago.  swresample is what ffmpeg calls their resampler, avresample is the one for libav