avfilter: add LIBVMAF filter

This one changes the previous vmaf patch to libvmaf to keep it separate from the
native implementation of vmaf inside ffmpeg later.

Signed-off-by: Ashish Singh <ashk43712@gmail.com>
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 8cc218aeed..2708fdb1df 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -9639,6 +9639,70 @@ The formula that generates the correction is:
 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
 distances from the focal point in the source and target images, respectively.
 
+@section libvmaf
+
+Obtain the average VMAF (Video Multi-Method Assessment Fusion)
+score between two input videos.
+
+This filter takes two input videos.
+
+Both video inputs must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+The obtained average VMAF score is printed through the logging system.
+
+It requires Netflix's vmaf library (libvmaf) as a pre-requisite.
+After installing the library it can be enabled using:
+@code{./configure --enable-libvmaf}.
+If no model path is specified it uses the default model: @code{vmaf_v0.6.1.pkl}.
+
+On the below examples the input file @file{main.mpg} being processed is
+compared with the reference file @file{ref.mpg}.
+
+The filter has following options:
+
+@table @option
+@item model_path
+Set the model path which is to be used for SVM.
+Default value: @code{"vmaf_v0.6.1.pkl"}
+
+@item log_path
+Set the file path to be used to store logs.
+
+@item log_fmt
+Set the format of the log file (xml or json).
+
+@item enable_transform
+Enables transform for computing vmaf.
+
+@item phone_model
+Invokes the phone model which will generate VMAF scores higher than in the
+regular model, which is more suitable for laptop, TV, etc. viewing conditions.
+
+@item psnr
+Enables computing psnr along with vmaf.
+
+@item ssim
+Enables computing ssim along with vmaf.
+
+@item ms_ssim
+Enables computing ms_ssim along with vmaf.
+
+@item pool
+Set the pool method to be used for computing vmaf.
+@end table
+
+For example:
+@example
+ffmpeg -i main.mpg -i ref.mpg -lavfi libvmaf -f null -
+@end example
+
+Example with options:
+@example
+ffmpeg -i main.mpg -i ref.mpg -lavfi libvmaf="psnr=1:enable-transform=1" -f null -
+@end example
+
 @section limiter
 
 Limits the pixel components values to the specified range [min, max].