From d259b20d877f6f9ae5a515ee58b0b440a4057c0b Mon Sep 17 00:00:00 2001
From: Paul Edwards <paul.edwards@semiformal.net>
Date: Sun, 27 Nov 2022 15:39:23 -0500
Subject: [PATCH 1/2] improve livestream script

---
 examples/livestream.sh | 46 ++++++++++++++++++++++++++++++------------
 1 file changed, 33 insertions(+), 13 deletions(-)

diff --git a/examples/livestream.sh b/examples/livestream.sh
index 18893a3ffce..733967947b3 100755
--- a/examples/livestream.sh
+++ b/examples/livestream.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-
+set -eo pipefail
 # Transcribe audio livestream by feeding ffmpeg output to whisper.cpp at regular intervals
 # Idea by @semiformal-net
 # ref: https://github.com/ggerganov/whisper.cpp/issues/185
@@ -10,14 +10,15 @@
 #
 
 url="http://a.files.bbci.co.uk/media/live/manifesto/audio/simulcast/hls/nonuk/sbr_low/ak/bbc_world_service.m3u8"
-step_ms=10000
+fmt=aac # the audio format extension of the stream (TODO: auto detect)
+step_s=30
 model="base.en"
 
 if [ -z "$1" ]; then
-    echo "Usage: $0 stream_url [step_ms] [model]"
+    echo "Usage: $0 stream_url [step_s] [model]"
     echo ""
     echo "  Example:"
-    echo "    $0 $url $step_ms $model"
+    echo "    $0 $url $step_s $model"
     echo ""
     echo "No url specified, using default: $url"
 else
@@ -25,7 +26,7 @@ else
 fi
 
 if [ -n "$2" ]; then
-    step_ms="$2"
+    step_s="$2"
 fi
 
 if [ -n "$3" ]; then
@@ -54,16 +55,35 @@ fi
 
 running=1
 
-trap "running=0" SIGINT SIGTERM
+#trap "running=0" SIGINT SIGTERM
 
-printf "[+] Transcribing stream with model '$model', step_ms $step_ms (press Ctrl+C to stop):\n\n"
+printf "[+] Transcribing stream with model '$model', step_s $step_s (press Ctrl+C to stop):\n\n"
 
+# continuous stream in native fmt (this file will grow forever!)
+ffmpeg -loglevel quiet -y -re -probesize 32 -i $url -c copy /tmp/whisper-live0.${fmt}  &
+if [ $? -ne 0 ]; then
+    printf "Error: ffmpeg failed to capture audio stream\n"
+    exit 1
+fi
+printf "Buffering audio. Please wait...\n"
+# For some reason, the initial buffer can end up smaller than step_s (even though we sleep for step_s)
+sleep $(($step_s*2))
+i=0
 while [ $running -eq 1 ]; do
-    ffmpeg -y -re -probesize 32 -i $url -ar 16000 -ac 1 -c:a pcm_s16le -t ${step_ms}ms /tmp/whisper-live0.wav > /dev/null 2> /tmp/whisper-live.err
-    if [ $? -ne 0 ]; then
-        printf "Error: ffmpeg failed to capture audio stream\n"
-        exit 1
+    # a handy bash built-in, SECONDS,
+    # > "This variable expands to the number of seconds since the shell was started. Assignment to this variable resets the count to the value assigned, and the expanded value becomes the value assigned
+    # > plus the number of seconds since the assignment."
+    SECONDS=0
+    # extract the next piece from the main file above and transcode to wav. -ss sets start time and nudges it by -0.5s to catch missing words (??)
+    if [ $i -gt 0 ]; then
+        ffmpeg -loglevel quiet -noaccurate_seek -i /tmp/whisper-live0.${fmt} -y -ar 16000 -ac 1 -c:a pcm_s16le -ss $(($i*$step_s-1)).5 -t $step_s /tmp/whisper-live.wav
+    else
+        ffmpeg -loglevel quiet -noaccurate_seek -i /tmp/whisper-live0.${fmt} -y -ar 16000 -ac 1 -c:a pcm_s16le -ss $(($i*$step_s)) -t $step_s /tmp/whisper-live.wav
     fi
-    mv /tmp/whisper-live0.wav /tmp/whisper-live.wav
-    ./main -t 8 -m ./models/ggml-small.en.bin -f /tmp/whisper-live.wav --no-timestamps -otxt 2> /tmp/whispererr | tail -n 1 &
+    ./main -t 8 -m ./models/ggml-base.en.bin -f /tmp/whisper-live.wav --no-timestamps -otxt 2> /tmp/whispererr | tail -n 1
+    echo
+    while [ $SECONDS -lt 30 ]; do
+        sleep 1
+    done
+    ((i=i+1))
 done

From 70df6b0f27cec65135bdb049470c897470e13207 Mon Sep 17 00:00:00 2001
From: semiformal-net <84111142+semiformal-net@users.noreply.github.com>
Date: Wed, 30 Nov 2022 19:39:57 -0500
Subject: [PATCH 2/2] Update examples/livestream.sh

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
---
 examples/livestream.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/livestream.sh b/examples/livestream.sh
index 733967947b3..b363448948f 100755
--- a/examples/livestream.sh
+++ b/examples/livestream.sh
@@ -82,7 +82,7 @@ while [ $running -eq 1 ]; do
     fi
     ./main -t 8 -m ./models/ggml-base.en.bin -f /tmp/whisper-live.wav --no-timestamps -otxt 2> /tmp/whispererr | tail -n 1
     echo
-    while [ $SECONDS -lt 30 ]; do
+    while [ $SECONDS -lt $step_s ]; do
         sleep 1
     done
     ((i=i+1))