From a105f49742d937e67dd546e29ca377c3cb52236c Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@pobox.com>
Date: Wed, 3 Nov 2021 10:43:29 -0700
Subject: [PATCH] retool mp3 id3 stuff for single-file

---
 llamigos-vp9-mp3-opus.m3u8 |  6 +-----
 timestamp-id3.php          | 34 +++++++++++++++++++++++++---------
 transcode-segment.php      |  7 +++++--
 3 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/llamigos-vp9-mp3-opus.m3u8 b/llamigos-vp9-mp3-opus.m3u8
index 97ad7cd..b5c83f8 100644
--- a/llamigos-vp9-mp3-opus.m3u8
+++ b/llamigos-vp9-mp3-opus.m3u8
@@ -2,7 +2,7 @@
 
 # Define the audio tracks for Opus and MP3
 #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="opus",NAME="English",LANGUAGE="en-US",AUTOSELECT=YES,DEFAULT=YES,CHANNELS="2",URI="caminandes-llamigos.webm.audio.opus.m3u8"
-#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="mp3",NAME="English",LANGUAGE="en-US",AUTOSELECT=YES,DEFAULT=YES,CHANNELS="2",URI="caminandes-llamigos.webm.audio.mp3.m3u8"
+#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="mp3",NAME="English",LANGUAGE="en-US",AUTOSELECT=YES,DEFAULT=YES,CHANNELS="2",URI="caminandes-llamigos.webm.audio.mp3.combined.m3u8"
 
 # Opus-based preferred
 #EXT-X-STREAM-INF:BANDWIDTH=5000000,RESOLUTION=1920x1080,FRAME-RATE=24.0,CODECS="vp09.00.10.08,opus",AUDIO="opus"
@@ -15,8 +15,6 @@ caminandes-llamigos.webm.480p.vp9.fast.m3u8
 caminandes-llamigos.webm.360p.vp9.fast.m3u8
 #EXT-X-STREAM-INF:BANDWIDTH=250000,RESOLUTION=426x240,FRAME-RATE=24.0,CODECS="vp09.00.10.08,opus",AUDIO="opus"
 caminandes-llamigos.webm.240p.vp9.fast.m3u8
-#EXT-X-STREAM-INF:BANDWIDTH=96000,CODECS="opus",AUDIO="opus"
-caminandes-llamigos.webm.audio.opus.m3u8
 
 # MP3 for Safari
 #EXT-X-STREAM-INF:BANDWIDTH=5000000,RESOLUTION=1920x1080,FRAME-RATE=24.0,CODECS="vp09.00.10.08,mp4a.40.34",AUDIO="mp3"
@@ -29,5 +27,3 @@ caminandes-llamigos.webm.480p.vp9.fast.m3u8
 caminandes-llamigos.webm.360p.vp9.fast.m3u8
 #EXT-X-STREAM-INF:BANDWIDTH=275000,RESOLUTION=426x240,FRAME-RATE=24.0,CODECS="vp09.00.10.08,mp4a.40.34",AUDIO="mp3"
 caminandes-llamigos.webm.240p.vp9.fast.m3u8
-#EXT-X-STREAM-INF:BANDWIDTH=128000,CODECS="mp4a.40.34",AUDIO="mp3"
-caminandes-llamigos.webm.audio.mp3.m3u8
diff --git a/timestamp-id3.php b/timestamp-id3.php
index 814b136..359bd2e 100644
--- a/timestamp-id3.php
+++ b/timestamp-id3.php
@@ -100,21 +100,24 @@ function process_mp3( $filename, $pts ) {
     print "$filename $pts $hex\n";
 
     $data = file_get_contents( $filename );
-    if ( substr( $data, 0, 3 ) == 'ID3' ) {
-        echo "SKIPPING already has ID3\n";
-    } else {
-        echo "ADDING ID3\n";
-        file_put_contents( $filename, "$tag$data" );
-    }
+    return "$tag$data";
 }
 
 $playlist = "caminandes-llamigos.webm.audio.mp3.m3u8";
+$playlist_out = "caminandes-llamigos.webm.audio.mp3.combined.m3u8";
+$outfile = "caminandes-llamigos.webm.audio.mp3";
 $lines = file( $playlist, FILE_IGNORE_NEW_LINES + FILE_SKIP_EMPTY_LINES );
 
 $pts = 0.0;
 $duration = 0.0;
+$lines_out = [];
+$chunks = [];
+$offset = 0;
 foreach ( $lines as $line ) {
 
+    // todo: create a single-file version
+    // and rewrite the manifest
+
     /*
     #EXTM3U
     #EXT-X-VERSION:3
@@ -126,16 +129,29 @@ foreach ( $lines as $line ) {
     #EXTINF:10.004898,
     caminandes-llamigos.webm.audio.mp3.0001.mp3
     ...
+
+    for output:
+    #EXT-X-BYTERANGE:132872@730
     */
     $matches = null;
     if ( preg_match( '/^#EXTINF:\s*(\d+(?:\.\d+)?),/', $line, $matches ) ) {
         $duration = floatval( $matches[1] );
-        continue;
-    } else if (preg_match( '/^#/', $line ) ) {
+    }
+    if (preg_match( '/^#/', $line ) ) {
+        $lines_out[] = $line;
         continue;
     }
     $filename = $line;
-    process_mp3( $filename, $pts );
+    $chunk = process_mp3( $filename, $pts );
+    $len = strlen( $chunk );
+    $lines_out[] = "#EXT-X-BYTERANGE:$len@$offset";
+    $lines_out[] = "$outfile";
+    $chunks[] = $chunk;
+    $offset += $len;
     $pts += $duration;
     $duration = 0;
 }
+
+
+file_put_contents( $outfile, implode( '', $chunks ) );
+file_put_contents( $playlist_out, implode( "\n", $lines_out ) );
\ No newline at end of file
diff --git a/transcode-segment.php b/transcode-segment.php
index 2478e18..749fd46 100644
--- a/transcode-segment.php
+++ b/transcode-segment.php
@@ -209,12 +209,13 @@ class Transcoder {
     private function ffmpeg( $options, $outfile, $container ) {
         $playlist = "$outfile.m3u8";
         $init = "$outfile.init.$container";
-        $segment = "$outfile.%04d.$container";
         if ( $container == 'mp4' ) {
             // HLS muxer seems to give the right options for fMP4
+            $segment = "$outfile.$container";
             $segmentOptions = [
                 '-f', 'hls',
                 '-hls_segment_type', 'fmp4',
+                '-hls_flags', 'single_file',
                 '-hls_time', '10',
                 '-hls_playlist_type', 'vod',
                 '-hls_fmp4_init_filename', $init,
@@ -223,7 +224,9 @@ class Transcoder {
             ];
         } elseif ( $container == 'mp3' ) {
             // For MP3, segment it raw.
-            // We'll need to postprocess to add an ID3 tag with timestamp.
+            // We'll need to postprocess to add an ID3 tag with timestamp
+            // and to reassemble into a file with byte ranges.
+            $segment = "$outfile.%04d.$container";
             $segmentOptions = [
                 '-f', 'segment',
                 '-segment_format_options', 'id3v2_version=0:write_xing=0:write_id3v1=0',