add bundled ffmpeg version to app when built in a container

Dockerfile

@@ -32,6 +32,9 @@ ARG default_gid="10000"
 COPY app /app
 COPY app/tubesync/local_settings.py.container /app/tubesync/local_settings.py
 
+# Append container bundled software versions
+RUN echo "ffmpeg_version = '${FFMPEG_VERSION}-static'" >> /app/common/third_party_versions.py
+
 # Add Pipfiles
 COPY Pipfile /app/Pipfile
 COPY Pipfile.lock /app/Pipfile.lock

app/common/context_processors.py

@@ -1,9 +1,10 @@
 from django.conf import settings
-from youtube_dl import version as yt_version
+from .third_party_versions import youtube_dl_version, ffmpeg_version
 
 
 def app_details(request):
     return {
         'app_version': str(settings.VERSION),
-        'youtube_dl_version': str(yt_version.__version__)
+        'youtube_dl_version': youtube_dl_version,
+        'ffmpeg_version': ffmpeg_version,
     }

app/common/templates/base.html

@@ -49,9 +49,13 @@
           <a href="{% url 'sync:dashboard' %}" class="nowrap">{% include 'tubesync.svg' with width='0.8rem' height='0.8rem' %} TubeSync</a>
           is an open source synchronisation tool to automatically download videos from online video platforms. The
           original code under a GPLv3 licence is available at
-          <a href="https://github.com/meeb/tubesync" class="nowrap"><i class="fab fa-github"></i> https://github.com/meeb/tubesync</a>.
+          <a href="https://github.com/meeb/tubesync" class="nowrap" target="_blank"><i class="fab fa-github"></i> https://github.com/meeb/tubesync</a>.
+        </p>
+        <p>
+          TubeSync version {{ app_version }} with
+          <a href="https://yt-dl.org/" target="_blank"><i class="fas fa-link"></i> youtube-dl</a> version {{ youtube_dl_version }} and 
+          <a href="https://ffmpeg.org/" target="_blank"><i class="fas fa-link"></i> FFmpeg</a> version {{ ffmpeg_version }}. 
         </p>
-        <p>TubeSync version {{ app_version }} with <a href="https://yt-dl.org/"><i class="fas fa-link"></i> youtube-dl</a> version {{ youtube_dl_version }}.</p>
       </div>
     </footer>
 

app/common/third_party_versions.py

@@ -0,0 +1,9 @@
+from youtube_dl import version as yt_version
+
+
+youtube_dl_version = str(yt_version.__version__)
+ffmpeg_version = '[shared system install]'
+
+
+# This file may contain data dynamically written during the container build process
+# that replaces the above versions. Do not edit below this line