decoder/{dsf,dsdiff}: precalculate bit rate

src/decoder/plugins/DsdiffDecoderPlugin.cxx

@@ -362,6 +362,7 @@ dsdiff_decode_chunk(DecoderClient &client, InputStream &is,
 		    unsigned channels, unsigned sample_rate,
 		    const offset_type total_bytes)
 {
+	const unsigned kbit_rate = channels * sample_rate / 1000;
 	const offset_type start_offset = is.GetOffset();
 
 	uint8_t buffer[8192];
@@ -408,7 +409,7 @@ dsdiff_decode_chunk(DecoderClient &client, InputStream &is,
 			bit_reverse_buffer(buffer, buffer + nbytes);
 
 		cmd = client.SubmitData(is, buffer, nbytes,
-					channels * sample_rate / 1000);
+					kbit_rate);
 	}
 
 	return true;

src/decoder/plugins/DsfDecoderPlugin.cxx

@@ -256,6 +256,7 @@ dsf_decode_chunk(DecoderClient &client, InputStream &is,
 		 offset_type n_blocks,
 		 bool bitreverse)
 {
+	const unsigned kbit_rate = channels * sample_rate / 1000;
 	const size_t block_size = channels * DSF_BLOCK_SIZE;
 	const offset_type start_offset = is.GetOffset();
 
@@ -291,7 +292,7 @@ dsf_decode_chunk(DecoderClient &client, InputStream &is,
 
 		cmd = client.SubmitData(is,
 					interleaved_buffer, block_size,
-					channels * sample_rate / 1000);
+					kbit_rate);
 		++i;
 	}