From 230d505377409e50635acb3877e06c52bbe5b3ca Mon Sep 17 00:00:00 2001
From: WeebDataHoarder <57538841+WeebDataHoarder@users.noreply.github.com>
Date: Mon, 6 Nov 2023 12:03:14 +0100
Subject: [PATCH] Fixed VFR pts end

---
 decoder/y4m/y4m.go     | 13 ++++++++++---
 utilities/timecodes.go | 16 +++++++++++++++-
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/decoder/y4m/y4m.go b/decoder/y4m/y4m.go
index 0764e91..fc20f48 100644
--- a/decoder/y4m/y4m.go
+++ b/decoder/y4m/y4m.go
@@ -10,6 +10,7 @@ import (
 	"io"
 	"strconv"
 	"strings"
+	"time"
 )
 
 type Decoder struct {
@@ -106,10 +107,16 @@ func (s *Decoder) IsVFR() bool {
 // FramePTS Returns -1 if not found
 func (s *Decoder) FramePTS(n int) int64 {
 	if s.IsVFR() {
-		if n >= len(s.timecodes) {
-			return -1
+		pts := s.timecodes.PTS(n)
+		if pts == -1 {
+			frameCount := len(s.timecodes) - 1
+			last := s.timecodes[frameCount]
+			if frameCount == 0 {
+				last = 0
+			}
+			pts = last + (s.timecodes.FallbackDuration() * time.Duration(n-frameCount+1)).Milliseconds()
 		}
-		return s.timecodes[n]
+		return pts
 	}
 	return int64(n)
 }
diff --git a/utilities/timecodes.go b/utilities/timecodes.go
index 73672c4..b1c86c7 100644
--- a/utilities/timecodes.go
+++ b/utilities/timecodes.go
@@ -6,11 +6,22 @@ import (
 	"github.com/nethruster/go-fraction"
 	"io"
 	"strings"
+	"time"
 )
 
-// Timecodes Entries in milliseconds
+// Timecodes Entries in milliseconds. First entry includes fallback duration, in time.Duration format
 type Timecodes []int64
 
+func (tc Timecodes) FallbackDuration() time.Duration {
+	return time.Duration(tc[0])
+}
+func (tc Timecodes) PTS(n int) int64 {
+	if n >= 0 && (n+1) < len(tc) {
+		return tc[n+1]
+	}
+	return -1
+}
+
 const timecodesv1Header = "# timecode format v1"
 
 func ParseTimecodesV1(reader io.Reader) (Timecodes, error) {
@@ -61,6 +72,9 @@ func ParseTimecodesV1(reader io.Reader) (Timecodes, error) {
 
 	var currentFrame int64
 
+	//fallback
+	tc = append(tc, (int64(time.Second)*assumedFraction.Numerator())/assumedFraction.Denominator())
+
 	for scanner.Scan() {
 		line := strings.ReplaceAll(strings.TrimSpace(scanner.Text()), " ", "")
 		if line == "" || line[0] == '#' {