diff --git a/src/decoder/Bridge.cxx b/src/decoder/Bridge.cxx
index b4d9fd076..98227a794 100644
--- a/src/decoder/Bridge.cxx
+++ b/src/decoder/Bridge.cxx
@@ -451,18 +451,18 @@ DecoderBridge::SubmitTimestamp(FloatDuration t) noexcept
 }
 
 DecoderCommand
-DecoderBridge::SubmitData(InputStream *is,
-			  const void *data, size_t length,
-			  uint16_t kbit_rate) noexcept
+DecoderBridge::SubmitAudio(InputStream *is,
+			   std::span<const std::byte> audio,
+			   uint16_t kbit_rate) noexcept
 {
 	assert(dc.state == DecoderState::DECODE);
 	assert(dc.pipe != nullptr);
-	assert(length % dc.in_audio_format.GetFrameSize() == 0);
+	assert(audio.size() % dc.in_audio_format.GetFrameSize() == 0);
 
 	DecoderCommand cmd = LockGetVirtualCommand();
 
 	if (cmd == DecoderCommand::STOP || cmd == DecoderCommand::SEEK ||
-	    length == 0)
+	    audio.empty())
 		return cmd;
 
 	assert(!initial_seek_pending);
@@ -486,7 +486,7 @@ DecoderBridge::SubmitData(InputStream *is,
 	cmd = DecoderCommand::NONE;
 
 	const size_t frame_size = dc.in_audio_format.GetFrameSize();
-	size_t data_frames = length / frame_size;
+	size_t data_frames = audio.size() / frame_size;
 
 	if (dc.end_time.IsPositive()) {
 		/* enforce the given end time */
@@ -501,7 +501,7 @@ DecoderBridge::SubmitData(InputStream *is,
 			/* past the end of the range: truncate this
 			   data submission and stop the decoder */
 			data_frames = remaining_frames;
-			length = data_frames * frame_size;
+			audio = audio.first(data_frames * frame_size);
 			cmd = DecoderCommand::STOP;
 		}
 	}
@@ -510,9 +510,7 @@ DecoderBridge::SubmitData(InputStream *is,
 		assert(dc.in_audio_format != dc.out_audio_format);
 
 		try {
-			auto result = convert->Convert({(const std::byte *)data, length});
-			data = result.data();
-			length = result.size();
+			audio = convert->Convert(audio);
 		} catch (...) {
 			/* the PCM conversion has failed - stop
 			   playback, since we have no better way to
@@ -524,7 +522,7 @@ DecoderBridge::SubmitData(InputStream *is,
 		assert(dc.in_audio_format == dc.out_audio_format);
 	}
 
-	while (length > 0) {
+	while (!audio.empty()) {
 		bool full;
 
 		auto *chunk = GetChunk();
@@ -544,11 +542,11 @@ DecoderBridge::SubmitData(InputStream *is,
 			continue;
 		}
 
-		const size_t nbytes = std::min(dest.size(), length);
+		const size_t nbytes = std::min(dest.size(), audio.size());
 
 		/* copy the buffer */
 
-		memcpy(dest.data(), data, nbytes);
+		memcpy(dest.data(), audio.data(), nbytes);
 
 		/* expand the music pipe chunk */
 
@@ -558,8 +556,7 @@ DecoderBridge::SubmitData(InputStream *is,
 			FlushChunk();
 		}
 
-		data = (const uint8_t *)data + nbytes;
-		length -= nbytes;
+		audio = audio.subspan(nbytes);
 
 		timestamp += dc.out_audio_format.SizeToTime<FloatDuration>(nbytes);
 	}
diff --git a/src/decoder/Bridge.hxx b/src/decoder/Bridge.hxx
index f29490793..bff5a10eb 100644
--- a/src/decoder/Bridge.hxx
+++ b/src/decoder/Bridge.hxx
@@ -177,9 +177,9 @@ public:
 	size_t Read(InputStream &is,
 		    void *buffer, size_t length) noexcept override;
 	void SubmitTimestamp(FloatDuration t) noexcept override;
-	DecoderCommand SubmitData(InputStream *is,
-				  const void *data, size_t length,
-				  uint16_t kbit_rate) noexcept override;
+	DecoderCommand SubmitAudio(InputStream *is,
+				   std::span<const std::byte> audio,
+				   uint16_t kbit_rate) noexcept override;
 	DecoderCommand SubmitTag(InputStream *is, Tag &&tag) noexcept override;
 	void SubmitReplayGain(const ReplayGainInfo *replay_gain_info) noexcept override;
 	void SubmitMixRamp(MixRampInfo &&mix_ramp) noexcept override;
diff --git a/src/decoder/Client.hxx b/src/decoder/Client.hxx
index 8f670885d..99e117737 100644
--- a/src/decoder/Client.hxx
+++ b/src/decoder/Client.hxx
@@ -24,7 +24,9 @@
 #include "Chrono.hxx"
 #include "input/Ptr.hxx"
 
+#include <cstddef>
 #include <cstdint>
+#include <span>
 
 struct AudioFormat;
 struct Tag;
@@ -41,7 +43,7 @@ public:
 	 * that it has read the song's meta data.
 	 *
 	 * @param audio_format the audio format which is going to be
-	 * sent to SubmitData()
+	 * sent to SubmitAudio()
 	 * @param seekable true if the song is seekable
 	 * @param duration the total duration of this song; negative if
 	 * unknown
@@ -128,14 +130,32 @@ public:
 	 * @return the current command, or DecoderCommand::NONE if there is no
 	 * command pending
 	 */
-	virtual DecoderCommand SubmitData(InputStream *is,
-					  const void *data, size_t length,
-					  uint16_t kbit_rate) noexcept = 0;
+	virtual DecoderCommand SubmitAudio(InputStream *is,
+					   std::span<const std::byte> audio,
+					   uint16_t kbit_rate) noexcept = 0;
 
-	DecoderCommand SubmitData(InputStream &is,
-				  const void *data, size_t length,
-				  uint16_t kbit_rate) noexcept {
-		return SubmitData(&is, data, length, kbit_rate);
+	DecoderCommand SubmitAudio(InputStream &is,
+				   std::span<const std::byte> audio,
+				   uint16_t kbit_rate) noexcept {
+		return SubmitAudio(&is, audio, kbit_rate);
+	}
+
+	template<typename T, std::size_t extent>
+	DecoderCommand SubmitAudio(InputStream *is,
+				   std::span<T, extent> audio,
+				   uint16_t kbit_rate) noexcept {
+		const std::span<const std::byte> audio_bytes =
+			std::as_bytes(audio);
+		return SubmitAudio(is, audio_bytes, kbit_rate);
+	}
+
+	template<typename T, std::size_t extent>
+	DecoderCommand SubmitAudio(InputStream &is,
+				   std::span<T, extent> audio,
+				   uint16_t kbit_rate) noexcept {
+		const std::span<const std::byte> audio_bytes =
+			std::as_bytes(audio);
+		return SubmitAudio(is, audio_bytes, kbit_rate);
 	}
 
 	/**
diff --git a/src/decoder/plugins/AdPlugDecoderPlugin.cxx b/src/decoder/plugins/AdPlugDecoderPlugin.cxx
index 07a761cfd..672cd2ebd 100644
--- a/src/decoder/plugins/AdPlugDecoderPlugin.cxx
+++ b/src/decoder/plugins/AdPlugDecoderPlugin.cxx
@@ -71,9 +71,9 @@ adplug_file_decode(DecoderClient &client, Path path_fs)
 		int16_t buffer[2048];
 		constexpr unsigned frames_per_buffer = std::size(buffer) / 2;
 		opl.update(buffer, frames_per_buffer);
-		cmd = client.SubmitData(nullptr,
-					buffer, sizeof(buffer),
-					0);
+		cmd = client.SubmitAudio(nullptr,
+					 std::span{buffer},
+					 0);
 	} while (cmd == DecoderCommand::NONE);
 
 	delete player;
diff --git a/src/decoder/plugins/AudiofileDecoderPlugin.cxx b/src/decoder/plugins/AudiofileDecoderPlugin.cxx
index b7f1b90e9..fd7e2f634 100644
--- a/src/decoder/plugins/AudiofileDecoderPlugin.cxx
+++ b/src/decoder/plugins/AudiofileDecoderPlugin.cxx
@@ -212,7 +212,7 @@ audiofile_stream_decode(DecoderClient &client, InputStream &is)
 	const auto kbit_rate = (uint16_t)
 		(is.GetSize() * uint64_t(8) / total_time.ToMS());
 
-	const auto frame_size = (unsigned)
+	const auto frame_size = (std::size_t)
 		afGetVirtualFrameSize(fh, AF_DEFAULT_TRACK, true);
 
 	client.Ready(audio_format, true, total_time);
@@ -226,9 +226,9 @@ audiofile_stream_decode(DecoderClient &client, InputStream &is)
 		if (nframes <= 0)
 			break;
 
-		cmd = client.SubmitData(nullptr,
-					chunk, nframes * frame_size,
-					kbit_rate);
+		cmd = client.SubmitAudio(nullptr,
+					 std::span{chunk, std::size_t(nframes) * frame_size},
+					 kbit_rate);
 
 		if (cmd == DecoderCommand::SEEK) {
 			AFframecount frame = client.GetSeekFrame();
diff --git a/src/decoder/plugins/DsdiffDecoderPlugin.cxx b/src/decoder/plugins/DsdiffDecoderPlugin.cxx
index 54412af20..c548e3321 100644
--- a/src/decoder/plugins/DsdiffDecoderPlugin.cxx
+++ b/src/decoder/plugins/DsdiffDecoderPlugin.cxx
@@ -417,8 +417,8 @@ dsdiff_decode_chunk(DecoderClient &client, InputStream &is,
 		if (lsbitfirst)
 			bit_reverse_buffer(buffer, buffer + nbytes);
 
-		cmd = client.SubmitData(is, buffer, nbytes,
-					kbit_rate);
+		cmd = client.SubmitAudio(is, std::span{buffer, nbytes},
+					 kbit_rate);
 	}
 
 	return true;
diff --git a/src/decoder/plugins/DsfDecoderPlugin.cxx b/src/decoder/plugins/DsfDecoderPlugin.cxx
index 88268670d..ca29b7423 100644
--- a/src/decoder/plugins/DsfDecoderPlugin.cxx
+++ b/src/decoder/plugins/DsfDecoderPlugin.cxx
@@ -289,9 +289,9 @@ dsf_decode_chunk(DecoderClient &client, InputStream &is,
 		uint8_t interleaved_buffer[MAX_CHANNELS * DSF_BLOCK_SIZE];
 		InterleaveDsfBlock(interleaved_buffer, buffer, channels);
 
-		cmd = client.SubmitData(is,
-					interleaved_buffer, block_size,
-					kbit_rate);
+		cmd = client.SubmitAudio(is,
+					 std::span{interleaved_buffer, block_size},
+					 kbit_rate);
 		++i;
 	}
 
diff --git a/src/decoder/plugins/FaadDecoderPlugin.cxx b/src/decoder/plugins/FaadDecoderPlugin.cxx
index 357043ca0..1089b4ab0 100644
--- a/src/decoder/plugins/FaadDecoderPlugin.cxx
+++ b/src/decoder/plugins/FaadDecoderPlugin.cxx
@@ -354,7 +354,7 @@ faad_stream_decode(DecoderClient &client, InputStream &is,
 		/* decode it */
 
 		NeAACDecFrameInfo frame_info;
-		const void *const decoded =
+		const auto decoded = (const int16_t *)
 			faad_decoder_decode(decoder, buffer, &frame_info);
 
 		if (frame_info.error > 0) {
@@ -391,9 +391,9 @@ faad_stream_decode(DecoderClient &client, InputStream &is,
 
 		/* send PCM samples to MPD */
 
-		cmd = client.SubmitData(is, decoded,
-					(size_t)frame_info.samples * 2,
-					bit_rate);
+		const std::span audio{decoded, (size_t)frame_info.samples};
+
+		cmd = client.SubmitAudio(is, audio, bit_rate);
 	} while (cmd != DecoderCommand::STOP);
 }
 
diff --git a/src/decoder/plugins/FfmpegDecoderPlugin.cxx b/src/decoder/plugins/FfmpegDecoderPlugin.cxx
index 384e31fcc..009d90cdf 100644
--- a/src/decoder/plugins/FfmpegDecoderPlugin.cxx
+++ b/src/decoder/plugins/FfmpegDecoderPlugin.cxx
@@ -205,7 +205,7 @@ PtsToPcmFrame(uint64_t pts, const AVStream &stream,
 }
 
 /**
- * Invoke DecoderClient::SubmitData() with the contents of an
+ * Invoke DecoderClient::SubmitAudio() with the contents of an
  * #AVFrame.
  */
 static DecoderCommand
@@ -227,9 +227,8 @@ FfmpegSendFrame(DecoderClient &client, InputStream *is,
 		skip_bytes = 0;
 	}
 
-	return client.SubmitData(is,
-				 output_buffer.data(), output_buffer.size(),
-				 codec_context.bit_rate / 1000);
+	return client.SubmitAudio(is, output_buffer,
+				  codec_context.bit_rate / 1000);
 }
 
 static DecoderCommand
diff --git a/src/decoder/plugins/FlacCommon.hxx b/src/decoder/plugins/FlacCommon.hxx
index f5c5a5809..fbb8cfa3b 100644
--- a/src/decoder/plugins/FlacCommon.hxx
+++ b/src/decoder/plugins/FlacCommon.hxx
@@ -46,7 +46,7 @@ struct FlacDecoder : public FlacInput {
 
 	/**
 	 * The kbit_rate parameter for the next
-	 * DecoderBridge::SubmitData() call.
+	 * DecoderBridge::SubmitAudio() call.
 	 */
 	uint16_t kbit_rate;
 
@@ -62,7 +62,7 @@ struct FlacDecoder : public FlacInput {
 
 	/**
 	 * Decoded PCM data obtained by our libFLAC write callback.
-	 * If this is non-empty, then DecoderBridge::SubmitData()
+	 * If this is non-empty, then DecoderBridge::SubmitAudio()
 	 * should be called.
 	 */
 	std::span<const std::byte> chunk = {};
diff --git a/src/decoder/plugins/FlacDecoderPlugin.cxx b/src/decoder/plugins/FlacDecoderPlugin.cxx
index d2e84b388..7a6d31034 100644
--- a/src/decoder/plugins/FlacDecoderPlugin.cxx
+++ b/src/decoder/plugins/FlacDecoderPlugin.cxx
@@ -152,10 +152,8 @@ FlacSubmitToClient(DecoderClient &client, FlacDecoder &d) noexcept
 	}
 
 	if (!d.chunk.empty()) {
-		auto cmd = client.SubmitData(d.GetInputStream(),
-					     d.chunk.data(),
-					     d.chunk.size(),
-					     d.kbit_rate);
+		auto cmd = client.SubmitAudio(d.GetInputStream(), d.chunk,
+					      d.kbit_rate);
 		d.chunk = {};
 		if (cmd != DecoderCommand::NONE)
 			return cmd;
diff --git a/src/decoder/plugins/FluidsynthDecoderPlugin.cxx b/src/decoder/plugins/FluidsynthDecoderPlugin.cxx
index e29fb6958..87adcb531 100644
--- a/src/decoder/plugins/FluidsynthDecoderPlugin.cxx
+++ b/src/decoder/plugins/FluidsynthDecoderPlugin.cxx
@@ -179,7 +179,7 @@ fluidsynth_file_decode(DecoderClient &client, Path path_fs)
 		if (ret != 0)
 			break;
 
-		cmd = client.SubmitData(nullptr, buffer, sizeof(buffer), 0);
+		cmd = client.SubmitAudio(nullptr, std::span{buffer}, 0);
 		if (cmd != DecoderCommand::NONE)
 			break;
 	}
diff --git a/src/decoder/plugins/GmeDecoderPlugin.cxx b/src/decoder/plugins/GmeDecoderPlugin.cxx
index ab108b912..a7eb650fb 100644
--- a/src/decoder/plugins/GmeDecoderPlugin.cxx
+++ b/src/decoder/plugins/GmeDecoderPlugin.cxx
@@ -216,7 +216,7 @@ gme_file_decode(DecoderClient &client, Path path_fs)
 			return;
 		}
 
-		cmd = client.SubmitData(nullptr, buf, sizeof(buf), 0);
+		cmd = client.SubmitAudio(nullptr, std::span{buf}, 0);
 		if (cmd == DecoderCommand::SEEK) {
 			unsigned where = client.GetSeekTime().ToMS();
 			gme_err = gme_seek(emu, where);
diff --git a/src/decoder/plugins/MadDecoderPlugin.cxx b/src/decoder/plugins/MadDecoderPlugin.cxx
index 3bb522d22..0e60bd0ba 100644
--- a/src/decoder/plugins/MadDecoderPlugin.cxx
+++ b/src/decoder/plugins/MadDecoderPlugin.cxx
@@ -185,13 +185,13 @@ private:
 
 	/**
 	 * Sends the synthesized current frame via
-	 * DecoderClient::SubmitData().
+	 * DecoderClient::SubmitAudio().
 	 */
 	DecoderCommand SubmitPCM(size_t start, size_t n) noexcept;
 
 	/**
 	 * Synthesize the current frame and send it via
-	 * DecoderClient::SubmitData().
+	 * DecoderClient::SubmitAudio().
 	 */
 	DecoderCommand SynthAndSubmit() noexcept;
 
@@ -805,9 +805,9 @@ MadDecoder::SubmitPCM(size_t i, size_t pcm_length) noexcept
 			       MAD_NCHANNELS(&frame.header));
 	num_samples *= MAD_NCHANNELS(&frame.header);
 
-	return client->SubmitData(input_stream, output_buffer,
-				  sizeof(output_buffer[0]) * num_samples,
-				  frame.header.bitrate / 1000);
+	return client->SubmitAudio(input_stream,
+				   std::span{output_buffer, num_samples},
+				   frame.header.bitrate / 1000);
 }
 
 inline DecoderCommand
diff --git a/src/decoder/plugins/MikmodDecoderPlugin.cxx b/src/decoder/plugins/MikmodDecoderPlugin.cxx
index f5f92fafd..867303e7a 100644
--- a/src/decoder/plugins/MikmodDecoderPlugin.cxx
+++ b/src/decoder/plugins/MikmodDecoderPlugin.cxx
@@ -171,7 +171,9 @@ mikmod_decoder_file_decode(DecoderClient &client, Path path_fs)
 	DecoderCommand cmd = DecoderCommand::NONE;
 	while (cmd == DecoderCommand::NONE && Player_Active()) {
 		ret = VC_WriteBytes(buffer, sizeof(buffer));
-		cmd = client.SubmitData(nullptr, buffer, ret, 0);
+		cmd = client.SubmitAudio(nullptr,
+					 std::span{buffer, std::size_t(ret)},
+					 0);
 	}
 
 	Player_Stop();
diff --git a/src/decoder/plugins/ModplugDecoderPlugin.cxx b/src/decoder/plugins/ModplugDecoderPlugin.cxx
index 834d30e5d..8b0b902b9 100644
--- a/src/decoder/plugins/ModplugDecoderPlugin.cxx
+++ b/src/decoder/plugins/ModplugDecoderPlugin.cxx
@@ -116,9 +116,9 @@ mod_decode(DecoderClient &client, InputStream &is)
 		if (ret <= 0)
 			break;
 
-		cmd = client.SubmitData(nullptr,
-					audio_buffer, ret,
-					0);
+		cmd = client.SubmitAudio(nullptr,
+					 std::span{audio_buffer, std::size_t(ret)},
+					 0);
 
 		if (cmd == DecoderCommand::SEEK) {
 			ModPlug_Seek(f, client.GetSeekTime().ToMS());
diff --git a/src/decoder/plugins/MpcdecDecoderPlugin.cxx b/src/decoder/plugins/MpcdecDecoderPlugin.cxx
index 86c608e77..774808d7f 100644
--- a/src/decoder/plugins/MpcdecDecoderPlugin.cxx
+++ b/src/decoder/plugins/MpcdecDecoderPlugin.cxx
@@ -241,9 +241,9 @@ mpcdec_decode(DecoderClient &client, InputStream &is)
 		long bit_rate = unsigned(frame.bits) * audio_format.sample_rate
 			/ (1000 * frame.samples);
 
-		cmd = client.SubmitData(is,
-					chunk, ret * sizeof(chunk[0]),
-					bit_rate);
+		cmd = client.SubmitAudio(is,
+					 std::span{chunk, ret},
+					 bit_rate);
 	} while (cmd != DecoderCommand::STOP);
 }
 
diff --git a/src/decoder/plugins/Mpg123DecoderPlugin.cxx b/src/decoder/plugins/Mpg123DecoderPlugin.cxx
index cf506b032..e8f82b5b9 100644
--- a/src/decoder/plugins/Mpg123DecoderPlugin.cxx
+++ b/src/decoder/plugins/Mpg123DecoderPlugin.cxx
@@ -253,7 +253,8 @@ mpd_mpg123_file_decode(DecoderClient &client, Path path_fs)
 
 		/* send to MPD */
 
-		cmd = client.SubmitData(nullptr, buffer, nbytes, info.bitrate);
+		cmd = client.SubmitAudio(nullptr, std::span{buffer, nbytes},
+					 info.bitrate);
 
 		if (cmd == DecoderCommand::SEEK) {
 			off_t c = client.GetSeekFrame();
diff --git a/src/decoder/plugins/OpenmptDecoderPlugin.cxx b/src/decoder/plugins/OpenmptDecoderPlugin.cxx
index b079c0102..b766d64bd 100644
--- a/src/decoder/plugins/OpenmptDecoderPlugin.cxx
+++ b/src/decoder/plugins/OpenmptDecoderPlugin.cxx
@@ -69,7 +69,6 @@ static void
 mod_decode(DecoderClient &client, InputStream &is)
 {
 	int ret;
-	char audio_buffer[OPENMPT_FRAME_SIZE];
 
 	const auto buffer = mod_loadfile(&openmpt_domain, &client, is);
 	if (buffer == nullptr) {
@@ -99,7 +98,8 @@ mod_decode(DecoderClient &client, InputStream &is)
 	mod.ctl_set("render.resampler.emulate_amiga", std::to_string((unsigned)openmpt_emulate_amiga));
 #endif
 
-	static constexpr AudioFormat audio_format(OPENMPT_SAMPLE_RATE, SampleFormat::FLOAT, 2);
+	static constexpr unsigned channels = 2;
+	static constexpr AudioFormat audio_format(OPENMPT_SAMPLE_RATE, SampleFormat::FLOAT, channels);
 	assert(audio_format.IsValid());
 
 	client.Ready(audio_format, is.IsSeekable(),
@@ -107,13 +107,16 @@ mod_decode(DecoderClient &client, InputStream &is)
 
 	DecoderCommand cmd;
 	do {
-		ret = mod.read_interleaved_stereo(OPENMPT_SAMPLE_RATE, OPENMPT_FRAME_SIZE / 2 / sizeof(float), (float*)audio_buffer);
+		float audio_buffer[OPENMPT_FRAME_SIZE / sizeof(float)];
+		ret = mod.read_interleaved_stereo(OPENMPT_SAMPLE_RATE,
+						  OPENMPT_FRAME_SIZE / channels / sizeof(float),
+						  audio_buffer);
 		if (ret <= 0)
 			break;
 
-		cmd = client.SubmitData(nullptr,
-					audio_buffer, ret * 2 * sizeof(float),
-					0);
+		cmd = client.SubmitAudio(nullptr,
+					 std::span{audio_buffer, ret * channels},
+					 0);
 
 		if (cmd == DecoderCommand::SEEK) {
 			mod.set_position_seconds(client.GetSeekTime().ToS());
diff --git a/src/decoder/plugins/OpusDecoderPlugin.cxx b/src/decoder/plugins/OpusDecoderPlugin.cxx
index c35914236..ccba79505 100644
--- a/src/decoder/plugins/OpusDecoderPlugin.cxx
+++ b/src/decoder/plugins/OpusDecoderPlugin.cxx
@@ -114,11 +114,9 @@ class MPDOpusDecoder final : public OggDecoder {
 	 */
 	unsigned previous_channels = 0;
 
-	size_t frame_size;
-
 	/**
 	 * The granulepos of the next sample to be submitted to
-	 * DecoderClient::SubmitData().  Negative if unkown.
+	 * DecoderClient::SubmitAudio().  Negative if unkown.
 	 * Initialized by OnOggBeginning().
 	 */
 	ogg_int64_t granulepos;
@@ -238,7 +236,6 @@ MPDOpusDecoder::OnOggBeginning(const ogg_packet &packet)
 	const AudioFormat audio_format(opus_sample_rate,
 				       SampleFormat::S16, channels);
 	client.Ready(audio_format, eos_granulepos > 0, duration);
-	frame_size = audio_format.GetFrameSize();
 
 	if (output_buffer == nullptr)
 		/* note: if we ever support changing the channel count
@@ -365,10 +362,10 @@ MPDOpusDecoder::HandleAudio(const ogg_packet &packet)
 	}
 
 	/* submit decoded samples to the DecoderClient */
-	const size_t nbytes = nframes * frame_size;
-	auto cmd = client.SubmitData(input_stream,
-				     data, nbytes,
-				     kbits);
+	const size_t n_samples = nframes * previous_channels;
+	auto cmd = client.SubmitAudio(input_stream,
+				      std::span{data, n_samples},
+				      kbits);
 	if (cmd != DecoderCommand::NONE)
 		throw cmd;
 
diff --git a/src/decoder/plugins/PcmDecoderPlugin.cxx b/src/decoder/plugins/PcmDecoderPlugin.cxx
index bd4dea739..8d9ab1f87 100644
--- a/src/decoder/plugins/PcmDecoderPlugin.cxx
+++ b/src/decoder/plugins/PcmDecoderPlugin.cxx
@@ -187,7 +187,7 @@ pcm_stream_decode(DecoderClient &client, InputStream &is)
 		auto r = buffer.Read();
 		/* round down to the nearest frame size, because we
 		   must not pass partial frames to
-		   DecoderClient::SubmitData() */
+		   DecoderClient::SubmitAudio() */
 		r = r.first(r.size() - r.size() % in_frame_size);
 		buffer.Consume(r.size());
 
@@ -209,7 +209,7 @@ pcm_stream_decode(DecoderClient &client, InputStream &is)
 		}
 
 		cmd = !r.empty()
-			? client.SubmitData(is, r.data(), r.size(), 0)
+			? client.SubmitAudio(is, r, 0)
 			: client.GetCommand();
 		if (cmd == DecoderCommand::SEEK) {
 			uint64_t frame = client.GetSeekFrame();
diff --git a/src/decoder/plugins/SidplayDecoderPlugin.cxx b/src/decoder/plugins/SidplayDecoderPlugin.cxx
index 266b12bd6..a730b32e5 100644
--- a/src/decoder/plugins/SidplayDecoderPlugin.cxx
+++ b/src/decoder/plugins/SidplayDecoderPlugin.cxx
@@ -419,15 +419,16 @@ sidplay_file_decode(DecoderClient &client, Path path_fs)
 
 #ifdef HAVE_SIDPLAYFP
 		/* libsidplayfp returns the number of samples */
-		const size_t nbytes = result * sizeof(buffer[0]);
+		const size_t n_samples = result;
 #else
 		/* libsidplay2 returns the number of bytes */
-		const size_t nbytes = result;
+		const size_t n_samples = result / sizeof(buffer[0]);
 #endif
 
 		client.SubmitTimestamp(FloatDuration(player.time()) / timebase);
 
-		cmd = client.SubmitData(nullptr, buffer, nbytes, 0);
+		cmd = client.SubmitAudio(nullptr, std::span{buffer, n_samples},
+					 0);
 
 		if (cmd == DecoderCommand::SEEK) {
 			unsigned data_time = player.time();
diff --git a/src/decoder/plugins/SndfileDecoderPlugin.cxx b/src/decoder/plugins/SndfileDecoderPlugin.cxx
index 253aef585..9bc22795f 100644
--- a/src/decoder/plugins/SndfileDecoderPlugin.cxx
+++ b/src/decoder/plugins/SndfileDecoderPlugin.cxx
@@ -227,9 +227,9 @@ sndfile_stream_decode(DecoderClient &client, InputStream &is)
 		if (num_frames <= 0)
 			break;
 
-		cmd = client.SubmitData(is,
-					buffer, num_frames * frame_size,
-					0);
+		cmd = client.SubmitAudio(is,
+					 std::span{buffer, num_frames * frame_size},
+					 0);
 		if (cmd == DecoderCommand::SEEK) {
 			sf_count_t c = client.GetSeekFrame();
 			c = sf_seek(sf, c, SEEK_SET);
diff --git a/src/decoder/plugins/VorbisDecoderPlugin.cxx b/src/decoder/plugins/VorbisDecoderPlugin.cxx
index aaf37ad0a..2339ff833 100644
--- a/src/decoder/plugins/VorbisDecoderPlugin.cxx
+++ b/src/decoder/plugins/VorbisDecoderPlugin.cxx
@@ -233,10 +233,10 @@ VorbisDecoder::SubmitSomePcm()
 
 	vorbis_synthesis_read(&dsp, n_frames);
 
-	const size_t nbytes = n_frames * frame_size;
-	auto cmd = client.SubmitData(input_stream,
-				     buffer, nbytes,
-				     0);
+	const std::size_t n_samples = n_frames * channels;
+	auto cmd = client.SubmitAudio(input_stream,
+				      std::span{buffer, n_samples},
+				      0);
 	if (cmd != DecoderCommand::NONE)
 		throw cmd;
 
diff --git a/src/decoder/plugins/WavpackDecoderPlugin.cxx b/src/decoder/plugins/WavpackDecoderPlugin.cxx
index 871b9e1a7..1617d82be 100644
--- a/src/decoder/plugins/WavpackDecoderPlugin.cxx
+++ b/src/decoder/plugins/WavpackDecoderPlugin.cxx
@@ -234,9 +234,12 @@ wavpack_decode(DecoderClient &client, WavpackContext *wpc, bool can_seek)
 		int bitrate = lround(WavpackGetInstantBitrate(wpc) / 1000);
 		format_samples(buffer, n_frames * audio_format.channels);
 
-		cmd = client.SubmitData(nullptr, buffer,
-					n_frames * output_frame_size,
-					bitrate);
+		cmd = client.SubmitAudio(nullptr,
+					 {
+						 (const std::byte *)buffer,
+						 n_frames * output_frame_size,
+					 },
+					 bitrate);
 	}
 }
 
diff --git a/src/decoder/plugins/WildmidiDecoderPlugin.cxx b/src/decoder/plugins/WildmidiDecoderPlugin.cxx
index fb9561153..9c67eb680 100644
--- a/src/decoder/plugins/WildmidiDecoderPlugin.cxx
+++ b/src/decoder/plugins/WildmidiDecoderPlugin.cxx
@@ -94,7 +94,9 @@ wildmidi_output(DecoderClient &client, midi *wm)
 	if (length <= 0)
 		return DecoderCommand::STOP;
 
-	return client.SubmitData(nullptr, buffer, length, 0);
+	return client.SubmitAudio(nullptr,
+				  std::span{buffer, std::size_t(length)},
+				  0);
 }
 
 static void
diff --git a/src/lib/chromaprint/DecoderClient.cxx b/src/lib/chromaprint/DecoderClient.cxx
index 4855f3b9d..d1ec1b986 100644
--- a/src/lib/chromaprint/DecoderClient.cxx
+++ b/src/lib/chromaprint/DecoderClient.cxx
@@ -63,23 +63,21 @@ ChromaprintDecoderClient::Ready(AudioFormat audio_format, bool,
 }
 
 DecoderCommand
-ChromaprintDecoderClient::SubmitData(InputStream *,
-				     const void *_data, size_t length,
-				     uint16_t) noexcept
+ChromaprintDecoderClient::SubmitAudio(InputStream *,
+				      std::span<const std::byte> audio,
+				      uint16_t) noexcept
 {
 	assert(ready);
 
-	if (length > remaining_bytes)
+	if (audio.size() > remaining_bytes)
 		remaining_bytes = 0;
 	else
-		remaining_bytes -= length;
-
-	std::span<const std::byte> src{(const std::byte *)_data, length};
+		remaining_bytes -= audio.size();
 
 	if (convert)
-		src = convert->Convert(src);
+		audio = convert->Convert(audio);
 
-	chromaprint.Feed(FromBytesStrict<const int16_t>(src));
+	chromaprint.Feed(FromBytesStrict<const int16_t>(audio));
 
 	return GetCommand();
 }
diff --git a/src/lib/chromaprint/DecoderClient.hxx b/src/lib/chromaprint/DecoderClient.hxx
index fe6ed6afa..bc0d0b114 100644
--- a/src/lib/chromaprint/DecoderClient.hxx
+++ b/src/lib/chromaprint/DecoderClient.hxx
@@ -93,9 +93,9 @@ public:
 		    void *buffer, size_t length) noexcept override;
 
 	void SubmitTimestamp(FloatDuration) noexcept override {}
-	DecoderCommand SubmitData(InputStream *is,
-				  const void *data, size_t length,
-				  uint16_t kbit_rate) noexcept override;
+	DecoderCommand SubmitAudio(InputStream *is,
+				   std::span<const std::byte> audio,
+				   uint16_t kbit_rate) noexcept override;
 
 	DecoderCommand SubmitTag(InputStream *, Tag &&) noexcept override {
 		return GetCommand();
diff --git a/test/DumpDecoderClient.cxx b/test/DumpDecoderClient.cxx
index 7941342bc..f59a00f74 100644
--- a/test/DumpDecoderClient.cxx
+++ b/test/DumpDecoderClient.cxx
@@ -91,16 +91,17 @@ DumpDecoderClient::SubmitTimestamp([[maybe_unused]] FloatDuration t) noexcept
 }
 
 DecoderCommand
-DumpDecoderClient::SubmitData([[maybe_unused]] InputStream *is,
-			      const void *data, size_t datalen,
-			      [[maybe_unused]] uint16_t kbit_rate) noexcept
+DumpDecoderClient::SubmitAudio([[maybe_unused]] InputStream *is,
+			       std::span<const std::byte> audio,
+			       [[maybe_unused]] uint16_t kbit_rate) noexcept
 {
 	if (kbit_rate != prev_kbit_rate) {
 		prev_kbit_rate = kbit_rate;
 		fprintf(stderr, "%u kbit/s\n", kbit_rate);
 	}
 
-	[[maybe_unused]] ssize_t nbytes = write(STDOUT_FILENO, data, datalen);
+	[[maybe_unused]] ssize_t nbytes = write(STDOUT_FILENO,
+						audio.data(), audio.size());
 	return GetCommand();
 }
 
diff --git a/test/DumpDecoderClient.hxx b/test/DumpDecoderClient.hxx
index 5f5827c36..274de839a 100644
--- a/test/DumpDecoderClient.hxx
+++ b/test/DumpDecoderClient.hxx
@@ -51,9 +51,9 @@ public:
 	size_t Read(InputStream &is,
 		    void *buffer, size_t length) noexcept override;
 	void SubmitTimestamp(FloatDuration t) noexcept override;
-	DecoderCommand SubmitData(InputStream *is,
-				  const void *data, size_t length,
-				  uint16_t kbit_rate) noexcept override;
+	DecoderCommand SubmitAudio(InputStream *is,
+				   std::span<const std::byte> audio,
+				   uint16_t kbit_rate) noexcept override;
 	DecoderCommand SubmitTag(InputStream *is, Tag &&tag) noexcept override;
 	void SubmitReplayGain(const ReplayGainInfo *replay_gain_info) noexcept override;
 	void SubmitMixRamp(MixRampInfo &&mix_ramp) noexcept override;