audio, audio/vorbis: ignore error at the initial Seek

This mitigates the issue of non-seekable source. At least,
vorbis.DecodeF32 and audio.NewPlayerF32 works.

Updates #3192

audio/player.go

@@ -408,7 +408,9 @@ func newTimeStream(r io.Reader, seekable bool, sampleRate int, bitDepthInBytes i
 		// Get the current position of the source.
 		pos, err := s.r.(io.Seeker).Seek(0, io.SeekCurrent)
 		if err != nil {
-			return nil, err
+			// Ignore the error, as the undelrying source might not support Seek (#3192).
+			// This happens when vorbis.Decode* is used, as vorbis.Stream is io.Seeker whichever the underlying source is.
+			pos = 0
 		}
 		s.pos.Store(pos)
 	}

audio/vorbis/vorbis_test.go

@@ -137,6 +137,8 @@ func TestNonSeeker(t *testing.T) {
 	if got, want := s.SampleRate(), audioContext.SampleRate(); got != want {
 		t.Errorf("s.SampleRate(): got: %d, want: %d", got, want)
 	}
+
+	// TODO: Check the result of io.ReadAll (#3192).
 }
 
 func TestNonSeekerF32(t *testing.T) {
@@ -150,4 +152,12 @@ func TestNonSeekerF32(t *testing.T) {
 	if got, want := s.Length(), int64(0); got != want {
 		t.Errorf("s.Length(): got: %d, want: %d", got, want)
 	}
+
+	buf, err := io.ReadAll(s)
+	if err != nil {
+		t.Errorf("io.ReadAll: %v", err)
+	}
+	if len(buf) == 0 {
+		t.Errorf("len(buf): got: %d, want: > 0", len(buf))
+	}
 }