BestAudioSource

Abstract
Author	Myrsloik
Version	r1
Download	bas-r1.7z
Category	Source filters
License	MIT
Discussion	Doom9 Thread

Description

A new sample accurate but somewhat slow FFmpeg based audio source filter for AviSynth. No indexing is required.

Requirements

• [x86]: AviSynth+ or AviSynth 2.6
• [x64]: AviSynth+

Syntax and Parameters

BestAudioSource (string "source", int "track", int "adjustdelay", bool "exactsamples", bool "enable_drefs", bool "use_absolute_path", float "drc_scale", string "varprefix")

string  source =

Path to audio file. Path can be omitted if the script is in the same folder as the audio file.

int  track = -1

Positive track numbers refer to the FFmpeg given stream number. Negative numbers refer to the nth audio track with -1 being the first.

int  adjustdelay = -1

Delay adjustment; not yet implemented.

bool  exactsamples = false

Set to true if you want opening files to be really slow but for some reason need a completely sample exact length.

bool  enable_drefs = false

Enable loading of external tracks, disabled by default.

bool  use_absolute_path = false

Allows loading of external tracks via absolute paths, disabled by default.

float  drc_scale = 0.0

Dynamic Range Scale Factor. The factor to apply to dynamic range values from the AC-3 stream. This factor is applied exponentially.

The default value is 0. There are 3 notable scale factor ranges:

• drc_scale == 0
  DRC disabled. Produces full range audio.
• 0 < drc_scale <= 1
  DRC enabled. Applies a fraction of the stream DRC value. Audio reproduction is between full range and full compression.
• drc_scale > 1
  DRC enabled. Applies drc_scale asymmetrically. Loud sounds are fully compressed. Soft sounds are enhanced.

string  varprefix = ""

Works the same as FFMS2.

• "BASCHANNEL_LAYOUT"
• "BASVALID_BITS"

Examples

BestAudioSource("blah.mp4", track=-1, adjustdelay=-1, exactsamples=false, enable_drefs=false, use_absolute_path=false, drc_scale=0)

Changelog

Version        Date            Changes

r1             2021/09/11      - First release. Everything except automatic delay adjustment implemented.
test8          2021/08/17      - Updated with several new options, including drc_scale. 
test7          2020/08/02      - VapourSynth: update for V4 api again; fixed all known bugs and should be fairly stable
test6          2020/06/23      - Fixes clips with more than 2^31 samples in VS and adds 24 bit output to AviSynth.
test5          2020/06/13      - Properly export the number of bits per sample
test4          2020/06/09      - Update for latest audio api revision 
test3          2020/01/26      - Fixes the channel mask variable that was previously almost always wrong in AviSynth.
                               - Also add VapourSynth support.
test2          2020/01/08      - Fixed output and new parameter "exactsamples"
test1          2020/01/07      - Initial release

Archived Downloads

Version	Download	Mirror
test8	BestAudioSource-test8.7z

External Links

• GitHub - Source code repository.

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