pcm/Export: split src_sample_format from alsa_channel_order

src/pcm/Export.cxx

@@ -32,10 +32,9 @@ PcmExport::Open(SampleFormat sample_format, unsigned _channels,
 {
 	assert(audio_valid_sample_format(sample_format));
 
+	src_sample_format = sample_format;
 	channels = _channels;
-	alsa_channel_order = params.alsa_channel_order
-		? sample_format
-		: SampleFormat::UNDEFINED;
+	alsa_channel_order = params.alsa_channel_order;
 
 #ifdef ENABLE_DSD
 	assert(params.dsd_mode != DsdMode::DOP ||
@@ -204,9 +203,9 @@ PcmExport::Params::CalcInputSampleRate(unsigned sample_rate) const noexcept
 ConstBuffer<void>
 PcmExport::Export(ConstBuffer<void> data) noexcept
 {
-	if (alsa_channel_order != SampleFormat::UNDEFINED)
+	if (alsa_channel_order)
 		data = ToAlsaChannelOrder(order_buffer, data,
-					  alsa_channel_order, channels);
+					  src_sample_format, channels);
 
 #ifdef ENABLE_DSD
 	switch (dsd_mode) {

src/pcm/Export.hxx

@@ -80,6 +80,11 @@ class PcmExport {
 	PcmBuffer reverse_buffer;
 
 	/**
+	 * The sample format of input data.
+	 */
+	SampleFormat src_sample_format;
+
+	/**
 	 * The number of channels.
 	 */
 	uint8_t channels;
@@ -87,12 +92,8 @@ class PcmExport {
 	/**
 	 * Convert the given buffer from FLAC channel order to ALSA
 	 * channel order using ToAlsaChannelOrder()?
-	 *
-	 * If this value is SampleFormat::UNDEFINED, then no channel
-	 * reordering is applied, otherwise this is the input sample
-	 * format.
 	 */
-	SampleFormat alsa_channel_order;
+	bool alsa_channel_order;
 
 #ifdef ENABLE_DSD
 public: