fix/gain-4dbU (#25)

Co-authored-by: Pbopbo <p.obernesser@freenet.de>
Reviewed-on: #25

src/auracast/auracast_config.py

@@ -55,7 +55,6 @@ class AuracastBigConfig(BaseModel):
     precode_wav: bool = False
     iso_que_len: int = 64
     num_bis: int = 1  # 1 = mono (FRONT_LEFT), 2 = stereo (FRONT_LEFT + FRONT_RIGHT)
-    input_gain_db: float = 0.0  # Software gain boost in dB applied before LC3 encoding (0 = off, max 20)
 
 class AuracastBigConfigDeu(AuracastBigConfig):
     id: int = 12
@@ -112,4 +111,5 @@ class AuracastConfigGroup(AuracastGlobalConfig):
     bigs: List[AuracastBigConfig] = [
         AuracastBigConfigDeu(),
     ]
-    analog_gain: int = 50  # ADC gain level for analog mode (10-60%)
+    analog_gain_db_left: float = 0.0  # ADC gain level for analog mode left channel (-12 to 18 dB)
+    analog_gain_db_right: float = 0.0  # ADC gain level for analog mode right channel (-12 to 18 dB)

src/auracast/multicast.py

@@ -862,13 +862,6 @@ class Streamer():
                 big['encoder'] = encoders[0]
                 big['precoded'] = False
 
-            # Pre-compute software gain multiplier from dB config (0 dB = 1.0 = no change)
-            gain_db = getattr(big_config[i], 'input_gain_db', 0.0)
-            gain_db = max(0.0, min(20.0, float(gain_db)))
-            big['_gain_linear'] = 10.0 ** (gain_db / 20.0) if gain_db > 0 else 0.0
-            if big['_gain_linear'] > 0.0:
-                logging.info("Software gain for BIG %d: +%.1f dB (linear %.3f)", i, gain_db, big['_gain_linear'])
-
         logging.info("Streaming audio...")
         bigs = self.bigs
         self.is_streaming = True
@@ -916,14 +909,6 @@ class Streamer():
                         stream_finished[i] = True
                         continue
 
-                    # Apply software gain boost if configured (> 0 dB)
-                    gain_lin = big.get('_gain_linear', 0.0)
-                    if gain_lin > 0.0:
-                        pcm_arr = np.frombuffer(pcm_frame, dtype=np.int16).astype(np.float32)
-                        pcm_arr *= gain_lin
-                        np.clip(pcm_arr, -32768, 32767, out=pcm_arr)
-                        pcm_frame = pcm_arr.astype(np.int16).tobytes()
-
                     # Compute RMS audio level (normalized 0.0-1.0) for level monitoring
                     pcm_samples = np.frombuffer(pcm_frame, dtype=np.int16).astype(np.float32)
                     rms = np.sqrt(np.mean(pcm_samples ** 2)) / 32768.0 if len(pcm_samples) > 0 else 0.0

src/auracast/server/multicast_frontend.py

@@ -198,35 +198,64 @@ else:
     start_stream, stop_stream = render_stream_controls(is_streaming, "Start Auracast", "Stop Auracast", running_mode, secondary_is_streaming)
 
 # Analog gain control (only for Analog mode, placed below start button)
-analog_gain_value = 50  # default (ALSA 10-60 range)
+analog_gain_db_left = 0  # default (dB)
-software_boost_db = 0  # default
+analog_gain_db_right = 0  # default (dB)
 if audio_mode == "Analog":
-    saved_analog_gain = saved_settings.get('analog_gain', 50)
+    if '_analog_gain_db_left' not in st.session_state:
-    # Convert persisted ALSA value (10-60) to display value (0-100)
+        st.session_state['_analog_gain_db_left'] = max(-12, min(18, int(saved_settings.get('analog_gain_db_left', 0))))
-    saved_display = int(round((saved_analog_gain - 10) * 100 / 50))
+    if '_analog_gain_db_right' not in st.session_state:
-    saved_display = max(0, min(100, saved_display))
+        st.session_state['_analog_gain_db_right'] = max(-12, min(18, int(saved_settings.get('analog_gain_db_right', 0))))
-    analog_gain_display = st.slider(
+    if '_gain_link_channels' not in st.session_state:
-        "Analog Input Gain",
+        st.session_state['_gain_link_channels'] = True
-        min_value=0,
+
-        max_value=100,
+    link_channels = st.checkbox(
-        value=saved_display,
+        "Link audio channel gain",
-        step=5,
+        key='_gain_link_channels',
-        disabled=is_streaming,
+        help="When enabled, Ch 2 mirrors Ch 1."
-        format="%d%%",
-        help="ADC gain level for both analog inputs. Default is 80%."
-    )
-    # Map display value (0-100) back to ALSA range (10-60)
-    analog_gain_value = int(round(10 + analog_gain_display * 50 / 100))
-    saved_boost = saved_settings.get('software_boost_db', 0)
-    software_boost_db = st.slider(
-        "Boost",
-        min_value=0,
-        max_value=20,
-        value=min(int(saved_boost), 20),
-        step=1,
-        disabled=is_streaming,
-        help="Digital gain boost applied before encoding (0-20 dB). Use this when the line-level signal is too quiet even at max ADC gain. Higher values may cause clipping on loud signals."
     )
+    _gain_col1, _gain_col2 = st.columns(2)
+    with _gain_col1:
+        analog_gain_db_left = st.slider(
+            "Ch 1 Input Gain",
+            min_value=-12,
+            max_value=18,
+            key='_analog_gain_db_left',
+            step=1,
+            format="%d dB",
+            help="ADC gain for channel 1 (-12 to 18 dB). Default is 0 dB."
+        )
+    with _gain_col2:
+        if link_channels:
+            st.session_state['_analog_gain_db_right'] = analog_gain_db_left
+        elif st.session_state.get('_prev_gain_link_channels', True):
+            # Transition: just unlinked — seed Ch 2 from Ch 1 so it doesn't jump to min
+            st.session_state['_analog_gain_db_right'] = analog_gain_db_left
+        st.session_state['_prev_gain_link_channels'] = link_channels
+        analog_gain_db_right = st.slider(
+            "Ch 2 Input Gain",
+            min_value=-12,
+            max_value=18,
+            key='_analog_gain_db_right',
+            step=1,
+            format="%d dB",
+            disabled=link_channels,
+            help="Uncheck 'Link audio channel gain' to adjust Ch 2 independently." if link_channels else "ADC gain for channel 2 (-12 to 18 dB). Default is 0 dB."
+        )
+    # Apply gain live while streaming whenever either slider value changes
+    if is_streaming:
+        prev_left = st.session_state.get('_prev_analog_gain_db_left')
+        prev_right = st.session_state.get('_prev_analog_gain_db_right')
+        if prev_left != analog_gain_db_left or prev_right != analog_gain_db_right:
+            try:
+                requests.post(
+                    f"{BACKEND_URL}/adc_gain",
+                    json={"gain_db_left": analog_gain_db_left, "gain_db_right": analog_gain_db_right},
+                    timeout=1,
+                )
+            except Exception:
+                pass
+        st.session_state['_prev_analog_gain_db_left'] = analog_gain_db_left
+        st.session_state['_prev_analog_gain_db_right'] = analog_gain_db_right
 
 # Audio level monitor (checkbox, not persisted across reloads)
 show_level_monitor = st.checkbox("Audio level monitor", value=False, disabled=not is_streaming,
@@ -684,8 +713,8 @@ else:
                     'immediate_rendering': immediate_rendering2,
                     'presentation_delay_ms': presentation_delay_ms2,
                     'qos_preset': qos_preset2,
-                    'analog_gain': analog_gain_value,
+                    'analog_gain_db_left': analog_gain_db_left,
-                    'software_boost_db': software_boost_db,
+                    'analog_gain_db_right': analog_gain_db_right,
                 }
 
         radio1_cfg = {
@@ -701,8 +730,8 @@ else:
             'presentation_delay_ms': presentation_delay_ms1,
             'qos_preset': qos_preset1,
             'stereo_mode': stereo_enabled,
-            'analog_gain': analog_gain_value,
+            'analog_gain_db_left': analog_gain_db_left,
-            'software_boost_db': software_boost_db,
+            'analog_gain_db_right': analog_gain_db_right,
         }
 
     if audio_mode == "Network - Dante":
@@ -1585,7 +1614,8 @@ if start_stream:
                 immediate_rendering=bool(cfg['immediate_rendering']),
                 presentation_delay_us=int(cfg['presentation_delay_ms'] * 1000),
                 qos_config=QOS_PRESET_MAP[cfg['qos_preset']],
-                analog_gain=cfg.get('analog_gain', 50),
+                analog_gain_db_left=cfg.get('analog_gain_db_left', 0.0),
+                analog_gain_db_right=cfg.get('analog_gain_db_right', 0.0),
                 bigs=[
                     auracast_config.AuracastBigConfig(
                         code=(cfg['stream_passwort'].strip() or None),
@@ -1598,7 +1628,6 @@ if start_stream:
                         sampling_frequency=q['rate'],
                         octets_per_frame=q['octets'],
                         num_bis=channels,  # 1=mono, 2=stereo - this determines the behavior
-                        input_gain_db=float(cfg.get('software_boost_db', 0)),
                     )
                 ],
             )

src/auracast/server/multicast_server.py

@@ -3,6 +3,7 @@ TODO: in the future the multicaster objects should run in their own threads or e
 
 """
 import os
+import re
 import logging as log
 import json
 from datetime import datetime
@@ -293,16 +294,18 @@ async def _init_i2c_on_startup() -> None:
             log.warning("Exception running i2cget (%s): %s", " ".join(read_cmd), e, exc_info=True)
 
 
-async def _set_adc_level(gain_percent: int = 50) -> None:
+async def _set_adc_level(gain_db_left: float = 0.0, gain_db_right: float = 0.0) -> None:
-    """Set ADC mixer level.
+    """Set ADC mixer gain in dB for left and right channels independently.
 
-    Runs: amixer -c 1 set 'ADC' x%
+    Runs: amixer -c 2 sset ADC {gain_db_left}dB,{gain_db_right}dB
     
     Args:
-        gain_percent: Gain level 10-60, default 50 (above 60% causes clipping/silence)
+        gain_db_left: Left channel gain in dB (-12 to 18), default 0
+        gain_db_right: Right channel gain in dB (-12 to 18), default 0
     """
-    gain_percent = max(10, min(60, gain_percent))
+    gain_db_left = max(-12.0, min(18.0, gain_db_left))
-    cmd = ["amixer", "-c", "1", "set", "ADC", f"{gain_percent}%"]
+    gain_db_right = max(-12.0, min(18.0, gain_db_right))
+    cmd = ["amixer", "-c", "2", "sset", "ADC", "--", f"{int(gain_db_left)}dB,{int(gain_db_right)}dB"]
     try:
         proc = await asyncio.create_subprocess_exec(
             *cmd,
@@ -311,15 +314,46 @@ async def _set_adc_level(gain_percent: int = 50) -> None:
         )
         stdout, stderr = await proc.communicate()
         if proc.returncode != 0:
-            log.warning(
+            log.error(
                 "amixer ADC level command failed (rc=%s): %s",
                 proc.returncode,
                 (stderr or b"" ).decode(errors="ignore").strip(),
             )
         else:
             log.info("amixer ADC level set successfully: %s", (stdout or b"" ).decode(errors="ignore").strip())
+            read_proc = await asyncio.create_subprocess_exec(
+                "amixer", "-c", "2", "sget", "ADC",
+                stdout=asyncio.subprocess.PIPE,
+                stderr=asyncio.subprocess.PIPE,
+            )
+            read_stdout, read_stderr = await read_proc.communicate()
+            if read_proc.returncode != 0:
+                log.error(
+                    "amixer ADC sget failed (rc=%s): %s",
+                    read_proc.returncode,
+                    (read_stderr or b"").decode(errors="ignore").strip(),
+                )
+            else:
+                sget_output = (read_stdout or b"").decode(errors="ignore")
+                actual = {}
+                for line in sget_output.splitlines():
+                    for ch_key, ch_name in (("left", "Front Left"), ("right", "Front Right")):
+                        if ch_name in line:
+                            m = re.search(r'\[(-?\d+(?:\.\d+)?)dB\]', line)
+                            if m:
+                                actual[ch_key] = round(float(m.group(1)))
+                expected_left = int(gain_db_left)
+                expected_right = int(gain_db_right)
+                if actual.get("left") != expected_left or actual.get("right") != expected_right:
+                    mismatch = (
+                        f"ADC level mismatch after set: expected L={expected_left}dB R={expected_right}dB, "
+                        f"got L={actual.get('left')}dB R={actual.get('right')}dB"
+                    )
+                    log.error(mismatch)
+                else:
+                    log.info("ADC level set successfully: L=%sdB R=%sdB", expected_left, expected_right)
     except Exception as e:
-        log.warning("Exception running amixer ADC level command: %s", e, exc_info=True)
+        log.error("Exception running amixer ADC level command: %s", e, exc_info=True)
 
 
 async def _stop_all() -> bool:
@@ -399,8 +433,9 @@ async def init_radio(transport: str, conf: auracast_config.AuracastConfigGroup,
             if input_device_name in ('ch1', 'ch2'):
                 audio_mode_persist = 'Analog'
                 # Set ADC gain level for analog mode
-                analog_gain = getattr(conf, 'analog_gain', 50)
+                analog_gain_db_left = getattr(conf, 'analog_gain_db_left', 0.0)
-                await _set_adc_level(analog_gain)
+                analog_gain_db_right = getattr(conf, 'analog_gain_db_right', 0.0)
+                await _set_adc_level(analog_gain_db_left, analog_gain_db_right)
             elif input_device_name in dante_channels:
                 audio_mode_persist = 'Network - Dante'
             else:
@@ -548,8 +583,8 @@ async def init_radio(transport: str, conf: auracast_config.AuracastConfigGroup,
             'immediate_rendering': getattr(conf, 'immediate_rendering', False),
             'assisted_listening_stream': getattr(conf, 'assisted_listening_stream', False),
             'analog_stereo_mode': getattr(conf.bigs[0], 'analog_stereo_mode', False) if conf.bigs else False,
-            'analog_gain': getattr(conf, 'analog_gain', 50),
+            'analog_gain_db_left': getattr(conf, 'analog_gain_db_left', 0.0),
-            'software_boost_db': getattr(conf.bigs[0], 'input_gain_db', 0.0) if conf.bigs else 0.0,
+            'analog_gain_db_right': getattr(conf, 'analog_gain_db_right', 0.0),
             'stream_password': (conf.bigs[0].code if conf.bigs and getattr(conf.bigs[0], 'code', None) else None),
             'big_ids': [getattr(big, 'id', DEFAULT_BIG_ID) for big in conf.bigs],
             'big_random_addresses': [getattr(big, 'random_address', DEFAULT_RANDOM_ADDRESS) for big in conf.bigs],
@@ -622,6 +657,28 @@ async def stop_audio():
         log.error("Exception in /stop_audio: %s", traceback.format_exc())
         raise HTTPException(status_code=500, detail=str(e))
 
+@app.post("/adc_gain")
+async def set_adc_gain(payload: dict):
+    """Set ADC gain in dB for left and right channels without restarting the stream.
+
+    Body: {"gain_db_left": float, "gain_db_right": float}
+    """
+    try:
+        gain_db_left = float(payload.get("gain_db_left", 0.0))
+        gain_db_right = float(payload.get("gain_db_right", 0.0))
+        await _set_adc_level(gain_db_left, gain_db_right)
+        # Persist the new values so they survive a restart
+        for load_fn, save_fn in [(load_stream_settings, save_stream_settings), (load_stream_settings2, save_stream_settings2)]:
+            s = load_fn() or {}
+            if s:
+                s['analog_gain_db_left'] = gain_db_left
+                s['analog_gain_db_right'] = gain_db_right
+                save_fn(s)
+        return {"status": "ok", "gain_db_left": gain_db_left, "gain_db_right": gain_db_right}
+    except Exception as e:
+        log.error("Exception in /adc_gain: %s", traceback.format_exc())
+        raise HTTPException(status_code=500, detail=str(e))
+
 @app.post("/stream_lc3")
 async def send_audio(audio_data: dict[str, str]):
     """Sends a block of pre-coded LC3 audio via the worker."""
@@ -818,7 +875,6 @@ async def _autostart_from_settings():
                         iso_que_len=1,
                         sampling_frequency=rate,
                         octets_per_frame=octets,
-                        input_gain_db=float(settings.get('software_boost_db', 0)),
                     )
                 ]
                 conf = auracast_config.AuracastConfigGroup(
@@ -828,7 +884,8 @@ async def _autostart_from_settings():
                     immediate_rendering=immediate_rendering,
                     assisted_listening_stream=assisted_listening_stream,
                     presentation_delay_us=pres_delay if pres_delay is not None else 40000,
-                    analog_gain=settings.get('analog_gain', 50),
+                    analog_gain_db_left=settings.get('analog_gain_db_left', 0.0),
+                    analog_gain_db_right=settings.get('analog_gain_db_right', 0.0),
                     bigs=bigs,
                 )
                 # Set num_bis for stereo mode if needed
@@ -973,7 +1030,6 @@ async def _autostart_from_settings():
                         iso_que_len=1,
                         sampling_frequency=rate,
                         octets_per_frame=octets,
-                        input_gain_db=float(settings.get('software_boost_db', 0)),
                     )
                 ]
                 conf = auracast_config.AuracastConfigGroup(
@@ -983,7 +1039,8 @@ async def _autostart_from_settings():
                     immediate_rendering=immediate_rendering,
                     assisted_listening_stream=assisted_listening_stream,
                     presentation_delay_us=pres_delay if pres_delay is not None else 40000,
-                    analog_gain=settings.get('analog_gain', 50),
+                    analog_gain_db_left=settings.get('analog_gain_db_left', 0.0),
+                    analog_gain_db_right=settings.get('analog_gain_db_right', 0.0),
                     bigs=bigs,
                 )
                 conf.qos_config = QOS_PRESET_MAP.get(saved_qos_preset, QOS_PRESET_MAP["Fast"])
@@ -1022,8 +1079,8 @@ async def _startup_autostart_event():
     _load_led_settings()
     _init_settings_cache_from_disk()
     await _init_i2c_on_startup()
-    # Ensure ADC mixer level is set at startup (default 50%)
+    # Ensure ADC mixer level is set at startup (default 0 dB)
-    await _set_adc_level(50)
+    await _set_adc_level(0.0, 0.0)
     refresh_pw_cache()
     log.info("[STARTUP] Scheduling autostart task")
     asyncio.create_task(_autostart_from_settings())