decoder/ffmpeg: move code to lib/ffmpeg/SampleFormat.hxx

src/decoder/plugins/FfmpegDecoderPlugin.cxx

@@ -30,6 +30,7 @@
 #include "lib/ffmpeg/Frame.hxx"
 #include "lib/ffmpeg/Format.hxx"
 #include "lib/ffmpeg/Codec.hxx"
+#include "lib/ffmpeg/SampleFormat.hxx"
 #include "../DecoderAPI.hxx"
 #include "FfmpegMetaData.hxx"
 #include "FfmpegIo.hxx"
@@ -361,22 +362,9 @@ gcc_const
 static SampleFormat
 ffmpeg_sample_format(enum AVSampleFormat sample_fmt) noexcept
 {
-	switch (sample_fmt) {
-	case AV_SAMPLE_FMT_S16:
-	case AV_SAMPLE_FMT_S16P:
-		return SampleFormat::S16;
-
-	case AV_SAMPLE_FMT_S32:
-	case AV_SAMPLE_FMT_S32P:
-		return SampleFormat::S32;
-
-	case AV_SAMPLE_FMT_FLT:
-	case AV_SAMPLE_FMT_FLTP:
-		return SampleFormat::FLOAT;
-
-	default:
-		break;
-	}
+	const auto result = Ffmpeg::FromFfmpegSampleFormat(sample_fmt);
+	if (result != SampleFormat::UNDEFINED)
+		return result;
 
 	char buffer[64];
 	const char *name = av_get_sample_fmt_string(buffer, sizeof(buffer),

src/lib/ffmpeg/SampleFormat.hxx

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2003-2019 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_FFMPEG_SAMPLE_FORMAT_HXX
+#define MPD_FFMPEG_SAMPLE_FORMAT_HXX
+
+#include "pcm/SampleFormat.hxx"
+
+extern "C" {
+#include <libavutil/samplefmt.h>
+}
+
+namespace Ffmpeg {
+
+/**
+ * Convert a FFmpeg #AVSampleFormat to a MPD #SampleFormat.  Returns
+ * SampleFormat::UNDEFINED if there is no direct mapping.
+ */
+constexpr SampleFormat
+FromFfmpegSampleFormat(AVSampleFormat sample_fmt) noexcept
+{
+	switch (sample_fmt) {
+	case AV_SAMPLE_FMT_S16:
+	case AV_SAMPLE_FMT_S16P:
+		return SampleFormat::S16;
+
+	case AV_SAMPLE_FMT_S32:
+	case AV_SAMPLE_FMT_S32P:
+		return SampleFormat::S32;
+
+	case AV_SAMPLE_FMT_FLT:
+	case AV_SAMPLE_FMT_FLTP:
+		return SampleFormat::FLOAT;
+
+	default:
+		return SampleFormat::UNDEFINED;
+	}
+}
+
+} // namespace Ffmpeg
+
+#endif