From a1b14bdf418327603da560fee7e1df9c5d384dfb Mon Sep 17 00:00:00 2001
From: Rien Maertens <rien.maertens@posteo.be>
Date: Sun, 19 Apr 2020 15:53:14 +0200
Subject: [PATCH] Measure troughput with -t

---
 README.md   |  1 +
 reStream.sh | 21 ++++++++++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 09f6c92..d2ce447 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,7 @@ reMarkable screen sharing over SSH.
 - `-o --output`: path of the output where the video should be recorded, as understood by `ffmpeg`; if this is `-`, the video is displayed in a new window and not recorded anywhere (default: `-`)
 - `-f --format`: when recording to an output, this option is used to force the encoding format; if this is `-`, `ffmpeg`’s auto format detection based on the file extension is used (default: `-`).
 - `-w --webcam`: record to a video4linux2 web cam device. By default the first found web cam is taken, this can be overwritten with `-o`. The video is scaled to 1280x720 to ensure compatibility with MS Teams, Skype for business and other programs which need this specific format.
+- `-t --throughput`: use `pv` to measure how much data throughput you have (good to experiment with parameters to speed up the pipeline)
 
 If you have problems, don't hesitate to [open an issue](https://github.com/rien/reStream/issues/new) or [send me an email](mailto:rien.maertens@posteo.be).
 
diff --git a/reStream.sh b/reStream.sh
index 2bc4a71..685389c 100755
--- a/reStream.sh
+++ b/reStream.sh
@@ -6,6 +6,7 @@ landscape=true             # rotate 90 degrees to the right
 output_path=-              # display output through ffplay
 format=-                   # automatic output format
 webcam=false               # not to a webcam
+measure_throughput=false   # measure how fast data is being transferred
 
 # loop through arguments and process them
 while [ $# -gt 0 ]; do
@@ -29,6 +30,10 @@ while [ $# -gt 0 ]; do
             shift
             shift
             ;;
+        -t | --throughput)
+            measure_throughput=true
+            shift
+            ;;
         -w | --webcam)
             webcam=true
             format="v4l2"
@@ -100,13 +105,26 @@ fi
 if [ -z "$compress" ]; then
     echo "Your remarkable does not have lz4."
     fallback_to_gzip
-elif ! lz4 -V; then
+elif ! lz4 -V > /dev/null; then
     echo "Your host does not have lz4."
     fallback_to_gzip
 else
     decompress="lz4 -d"
 fi
 
+# use pv to measure throughput if desired, else we just pipe through cat
+if $measure_throughput; then
+    if ! pv --version > /dev/null; then
+        echo "You need to install pv to measure data throughput."
+        exit 1
+    else
+        loglevel="error" # verbose ffmpeg output interferes with pv
+        host_passthrough="pv"
+    fi
+else
+    host_passthrough="cat"
+fi
+
 # list of ffmpeg filters to apply
 video_filters=""
 
@@ -164,6 +182,7 @@ set -e # stop if an error occurs
 # shellcheck disable=SC2086
 ssh_cmd "$read_loop" \
     | $decompress \
+    | $host_passthrough \
     | "$output_cmd" \
         -vcodec rawvideo \
         -loglevel "$loglevel" \