diff --git a/cmd/ffwebp/main.go b/cmd/ffwebp/main.go
index d512bf3..4ad3a93 100644
--- a/cmd/ffwebp/main.go
+++ b/cmd/ffwebp/main.go
@@ -46,6 +46,10 @@ func main() {
 			Aliases: []string{"c"},
 			Usage:   "force output codec (jpeg, png, ...)",
 		},
+		&cli.StringFlag{
+			Name:  "input.codec",
+			Usage: "force input codec, skip sniffing (jpeg, png, ...)",
+		},
 		&cli.BoolFlag{
 			Name:    "sniff",
 			Aliases: []string{"f"},
@@ -265,7 +269,9 @@ func run(_ context.Context, cmd *cli.Command) error {
 func processOne(input, output string, cmd *cli.Command, common *opts.Common, logger io.Writer) error {
 	var (
 		reader io.Reader    = os.Stdin
-		writer *countWriter = &countWriter{w: os.Stdout}
+		writer *countWriter = &countWriter{
+			w: os.Stdout,
+		}
 	)
 
 	if input != "-" {
@@ -283,14 +289,16 @@ func processOne(input, output string, cmd *cli.Command, common *opts.Common, log
 		logx.Fprintf(logger, "reading input from <stdin>\n")
 	}
 
-	sniffed, reader2, err := codec.Sniff(reader, input, cmd.Bool("sniff"))
+	forced := cmd.String("input.codec")
+
+	sniffed, reader2, err := codec.Sniff(reader, input, forced, cmd.Bool("sniff"))
 	if err != nil {
 		return err
 	}
 
 	reader = reader2
 
-	logx.Fprintf(logger, "sniffed codec: %s (%q)\n", sniffed.Codec, sniffed)
+	logx.Fprintf(logger, "sniffed codec: %s (%q, forced=%v)\n", sniffed.Codec, sniffed, forced != "")
 
 	var mappedFromDir bool
 
diff --git a/internal/codec/detect.go b/internal/codec/detect.go
index 8ca7ca2..f36a58e 100644
--- a/internal/codec/detect.go
+++ b/internal/codec/detect.go
@@ -30,7 +30,20 @@ func (s *Sniffed) String() string {
 	return builder.String()
 }
 
-func Sniff(reader io.Reader, input string, ignoreExtension bool) (*Sniffed, io.Reader, error) {
+func Sniff(reader io.Reader, input, force string, ignoreExtension bool) (*Sniffed, io.Reader, error) {
+	if force != "" {
+		codec, err := FindCodec(strings.ToLower(force), false)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		return &Sniffed{
+			Header:     []byte(force),
+			Confidence: 100,
+			Codec:      codec,
+		}, reader, nil
+	}
+
 	var (
 		hintedExt   string
 		hintedCodec Codec
@@ -38,6 +51,7 @@ func Sniff(reader io.Reader, input string, ignoreExtension bool) (*Sniffed, io.R
 
 	if !ignoreExtension {
 		hintedExt = strings.ToLower(strings.TrimPrefix(filepath.Ext(input), "."))
+
 		if hintedExt != "" {
 			hintedCodec, _ = FindCodec(hintedExt, false)
 		}