From 06f1b98082b9e91115b9667dd413cc0eff88f5ce Mon Sep 17 00:00:00 2001
From: Luke Curley <lcurley@twitch.tv>
Date: Tue, 8 Nov 2022 13:18:35 +0000
Subject: [PATCH] Initial work on supporting renditions.

---
 README.md      |  4 ++--
 media/generate | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100755 media/generate

diff --git a/README.md b/README.md
index f13794d..1e16702 100644
--- a/README.md
+++ b/README.md
@@ -45,12 +45,12 @@ This demo simulates a live stream by reading a file from disk and sleeping based
 
 Download your favorite media file:
 ```
-wget http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4 -O media/combined.mp4
+wget http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4 -O media/source.mp4
 ```
 
 Use ffmpeg to create a LL-DASH playlist. This creates a segment every 2s and MP4 fragment every 10ms.
 ```
-ffmpeg -i media/combined.mp4 -f dash -use_timeline 0 -r:v 24 -g:v 48 -keyint_min:v 48 -sc_threshold:v 0 -tune zerolatency -streaming 1 -ldash 1 -seg_duration 2 -frag_duration 0.01 -frag_type duration media/fragmented.mpd
+ffmpeg -i media/source.mp4 -f dash -use_timeline 0 -r:v 24 -g:v 48 -keyint_min:v 48 -sc_threshold:v 0 -tune zerolatency -streaming 1 -ldash 1 -seg_duration 2 -frag_duration 0.01 -frag_type duration media/fragmented.mpd
 ```
 
 You can increase the `frag_duration` (microseconds) to slightly reduce the file size in exchange for higher latency.
diff --git a/media/generate b/media/generate
new file mode 100755
index 0000000..110f401
--- /dev/null
+++ b/media/generate
@@ -0,0 +1,18 @@
+#!/bin/bash
+ffmpeg -i source.mp4 \
+    -f dash -ldash 1 \
+	-c:v libx264 \
+    -preset veryfast -tune zerolatency \
+	-c:a aac \
+	-b:a 128k -ac 2 -ar 44100 \
+	-map v:0 -s:v:0 1280x720 -b:v:0 3M   \
+	-map v:0 -s:v:1 854x480  -b:v:1 1.1M \
+	-map v:0 -s:v:2 640x360  -b:v:2 365k \
+	-map 0:a \
+	-force_key_frames "expr:gte(t,n_forced*2)" \
+	-sc_threshold 0 \
+	-streaming 1 \
+	-use_timeline 0 \
+	-seg_duration 2 -frag_duration 0.01 \
+	-frag_type duration \
+	playlist.mpd