From 26c1297c16432f07e05da1bb941de09a12db8fa8 Mon Sep 17 00:00:00 2001
From: "byte[]" <byteslice@airmail.cc>
Date: Fri, 12 Mar 2021 19:17:11 -0500
Subject: [PATCH] strip and remux uploaded videos, fixes
 philomena-dev/philomena#104

---
 lib/philomena/processors/webm.ex | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/lib/philomena/processors/webm.ex b/lib/philomena/processors/webm.ex
index 52f81d7a..342135ce 100644
--- a/lib/philomena/processors/webm.ex
+++ b/lib/philomena/processors/webm.ex
@@ -5,16 +5,18 @@ defmodule Philomena.Processors.Webm do
   def process(analysis, file, versions) do
     dimensions = analysis.dimensions
     duration = analysis.duration
-    preview = preview(duration, file)
-    palette = gif_palette(file, duration)
-    mp4 = scale_mp4_only(file, dimensions, dimensions)
+    stripped = strip(file)
+    preview = preview(duration, stripped)
+    palette = gif_palette(stripped, duration)
+    mp4 = scale_mp4_only(stripped, dimensions, dimensions)
 
     {:ok, intensities} = Intensities.file(preview)
 
     scaled =
-      Enum.flat_map(versions, &scale_if_smaller(file, mp4, palette, duration, dimensions, &1))
+      Enum.flat_map(versions, &scale_if_smaller(stripped, mp4, palette, duration, dimensions, &1))
 
     %{
+      replace_original: stripped,
       intensities: intensities,
       thumbnails: scaled ++ [{:copy, preview, "rendered.png"}]
     }
@@ -35,6 +37,28 @@ defmodule Philomena.Processors.Webm do
     preview
   end
 
+  defp strip(file) do
+    stripped = Briefly.create!(extname: ".webm")
+
+    {_output, 0} =
+      System.cmd("ffmpeg", [
+        "-loglevel",
+        "0",
+        "-y",
+        "-i",
+        file,
+        "-map_metadata",
+        "-1",
+        "-c",
+        "copy",
+        "-map",
+        "0",
+        stripped
+      ])
+
+    stripped
+  end
+
   defp scale_if_smaller(_file, mp4, _palette, _duration, _dimensions, {:full, _target_dim}) do
     [
       {:symlink_original, "full.webm"},