From f187af747be95c93443b2f6a553d141490122130 Mon Sep 17 00:00:00 2001
From: Saxon <saxon@ausocean.org>
Date: Tue, 7 Jan 2020 12:52:31 +1030
Subject: [PATCH] codec/mjpeg/jpeg.go: removing panics inside ParsePayload in
 favour of errors

---
 codec/mjpeg/jpeg.go | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/codec/mjpeg/jpeg.go b/codec/mjpeg/jpeg.go
index c3277b9f..be3c648c 100644
--- a/codec/mjpeg/jpeg.go
+++ b/codec/mjpeg/jpeg.go
@@ -85,9 +85,12 @@ const (
 	sosComponentsInScan = 3  // Number of components in scan.
 )
 
+// Errors returned from ParsePayload.
 var (
-	errNoQTable  = errors.New("no quantization table")
-	errReservedQ = errors.New("q value is reserved")
+	ErrNoQTable             = errors.New("no quantization table")
+	ErrReservedQ            = errors.New("q value is reserved")
+	ErrUnimplementedType    = errors.New("unimplemented RTP/JPEG type")
+	ErrUnsupportedPrecision = errors.New("unsupported precision")
 )
 
 // Slices used in the creation of huffman tables.
@@ -205,7 +208,7 @@ func (c *Context) ParsePayload(p []byte, m bool) error {
 	}
 
 	if t > 1 {
-		panic("unimplemented RTP/JPEG type")
+		return ErrUnimplementedType
 	}
 
 	// Parse quantization table if our offset is 0.
@@ -220,7 +223,7 @@ func (c *Context) ParsePayload(p []byte, m bool) error {
 			idx += 3
 
 			if prec != 0 {
-				panic("unsupported precision")
+				return ErrUnsupportedPrecision
 			}
 
 			if qLen > 0 {
@@ -233,7 +236,7 @@ func (c *Context) ParsePayload(p []byte, m bool) error {
 				}
 			} else {
 				if q == 255 {
-					return errNoQTable
+					return ErrNoQTable
 				}
 
 				if c.qTablesLen[q-128] == 0 {
@@ -245,7 +248,7 @@ func (c *Context) ParsePayload(p []byte, m bool) error {
 			}
 		} else { // q <= 127
 			if q == 0 || q > 99 {
-				return errReservedQ
+				return ErrReservedQ
 			}
 			qTable = defaultQTable(int(q))
 			qLen = len(qTable)