we require C11 since including stdatomic and FFmpeg v4

docs/framework.txt

@@ -53,7 +53,7 @@ Basic Design Information:
 
 	MLT is written in C. 
 
-	The framework has no dependencies other than the standard C99 and POSIX 
+    The framework has no dependencies other than the standard C11 and POSIX
 	libraries. 
 
 	It follows a basic Object Oriented design paradigm, and as such, much of the

docs/install.txt

@@ -19,7 +19,7 @@ Last Revision: 2013-09-07
       * melt             - A media playing test application (*)
       * mlt++            - C++ wrapper for framework
       * modules          - All services are defined here
-         * avformat      - FFmpeg/Libav dependent services
+         * avformat      - FFmpeg dependent services
          * avsync        - services to help test audio/video synchronization
          * core          - independent MLT services
          * decklink      - Blackmagick Design SDI/HDMI services
@@ -65,7 +65,7 @@ Last Revision: 2013-09-07
 
    The MLT core is dependent on:
 
-   * a C99 compliant C compiler
+   * a C11 compliant C compiler
    * posix threading (pthread)
    * standard posix libraries (libc)
 
@@ -74,7 +74,7 @@ Last Revision: 2013-09-07
    The modules have the following dependencies:
 
    | *Module* | *Description* |
-   | avformat | [[http://www.ffmpeg.org][FFmpeg]] or [[http://www.libav.org][libav]] v0.7 or later |
+   | avformat | [[http://www.ffmpeg.org][FFmpeg]] v4.0 or later |
    | dv       | [[http://libdv.sf.net][libdv]] 0.102 or later |
    | gtk2     | [[http://www.gtk.org][GTK2]] and associated dependencies |
    | jackrack | [[http://jackaudio.org][JACK]], [[http://www.xmlsoft.org/][libxml2]], and ladspa.h |

src/melt/melt.c

@@ -1,6 +1,6 @@
 /*
  * melt.c -- MLT command line utility
- * Copyright (C) 2002-2020 Meltytech, LLC
+ * Copyright (C) 2002-2021 Meltytech, LLC
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -875,7 +875,7 @@ int main( int argc, char **argv )
 		else if ( !strcmp( argv[ i ], "-version" ) || !strcmp( argv[ i ], "--version" ) )
 		{
 			fprintf( stdout, "%s " VERSION "\n"
-				"Copyright (C) 2002-2020 Meltytech, LLC\n"
+				"Copyright (C) 2002-2021 Meltytech, LLC\n"
 				"<https://www.mltframework.org/>\n"
 				"This is free software; see the source for copying conditions.  There is NO\n"
 				"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n",

src/modules/avformat/configure

@@ -5,8 +5,7 @@ then
 	cat << EOF
 FFmpeg/avformat options:
 
-  This module requires at least FFmpeg v2.4 or Libav 12.
-  Features using libavfilter requires FFmpeg (not Libav).
+  This module requires at least FFmpeg v4.0.
 
   --avformat-shared=path  - Link against a shared installation of libavformat (default)
   --avformat-static=path  - Link against a static build of libavformat

src/modules/avformat/consumer_avformat.yml

@@ -15,9 +15,9 @@ tags:
   - Video
 description: Write or stream audio and/or video using FFmpeg.
 notes: >
-  The avformat consumer uses the FFmpeg/libav libraries to encode to a file or
+  The avformat consumer uses the FFmpeg libraries to encode to a file or
   network stream. You can get a lot of information about how to encode with
-  FFmpeg all over the web including FFmpeg/libav's web site. With melt, you
+  FFmpeg all over the web including FFmpeg's web site. With melt, you
   simply need to add "-consumer avformat:output.file" to the command line
   followed by the encoding parameters by translating ffmpeg's '-option value'
   syntax to melt's 'option=value' syntax.