compot-dev · Oct 12, 2026 · Oct 12, 2026 · Oct 12, 2026 · Oct 12, 2026 · qodo-free-for-open-source-projects
diff --git a/README.md b/README.md
@@ -34,7 +34,7 @@ A beta channel is available on [Google Play](https://play.google.com/apps/intern
 ## Features
 
 - **Video:** RTSP playback, hardware H.264/H.265 decoding via MediaCodec
-- **Audio:** AAC (RFC 3640 `mpeg4-generic`, ADTS), G.711 μ-law/A-law, L16 PCM (mono/stereo)
+- **Audio:** AAC (RFC 3640 `mpeg4-generic`, ADTS, MP4A-LATM), Opus, G.711 μ-law/A-law, L16 PCM (mono/stereo)
 - **Display:** single camera, or Quad mode with 4 cameras at once
 - **Controls:** pinch-to-zoom, pan, double-tap to reset, Android TV remote (Leanback launcher)
 - **Network:** Basic and Digest authentication, RTSP keepalive, automatic reconnection with exponential back-off, connection-quality indicator
@@ -93,7 +93,7 @@ Shows all configured slots in a 2×2 grid. Each cell has its own connection and
 >
 > - **RTSP over TCP only.** No UDP or multicast — [#7](https://github.com/OpenIPC/decoder/issues/7)
 > - **Only 4 camera slots** — [#13](https://github.com/OpenIPC/decoder/issues/13)
-> - **Audio formats not supported:** MP4A-LATM, Opus, G.726, and AAC frames split across RTP packets — [#14](https://github.com/OpenIPC/decoder/issues/14)
+> - **G.726 audio is not supported** — [#14](https://github.com/OpenIPC/decoder/issues/14)
 > - **Possible dependency on Google services (GAPPS)** on some devices; under investigation, so disable GAPPS with care — [#15](https://github.com/OpenIPC/decoder/issues/15)
 > - **Credentials are stored and sent in clear text** (plain RTSP/HTTP; Basic auth is sent unless the camera asks for Digest) — [#16](https://github.com/OpenIPC/decoder/issues/16)
 >

diff --git a/README.ru.md b/README.ru.md
@@ -34,7 +34,7 @@
 ## Возможности
 
 - **Видео:** воспроизведение RTSP, аппаратное декодирование H.264/H.265 через MediaCodec
-- **Звук:** AAC (RFC 3640 `mpeg4-generic`, ADTS), G.711 μ-law/A-law, L16 PCM (моно и стерео)
+- **Звук:** AAC (RFC 3640 `mpeg4-generic`, ADTS, MP4A-LATM), Opus, G.711 μ-law/A-law, L16 PCM (моно и стерео)
 - **Режимы:** одна камера или Quad — 4 камеры на одном экране
 - **Управление:** масштаб двумя пальцами, перемещение, сброс двойным касанием, пульт Android TV (Leanback)
 - **Сеть:** авторизация Basic и Digest, RTSP keepalive, автоматическое переподключение с растущей задержкой, индикатор качества связи
@@ -93,7 +93,7 @@
 >
 > - **Только RTSP поверх TCP.** UDP и multicast не поддерживаются — [#7](https://github.com/OpenIPC/decoder/issues/7)
 > - **Только 4 слота для камер** — [#13](https://github.com/OpenIPC/decoder/issues/13)
-> - **Не поддерживаются форматы звука** MP4A-LATM, Opus, G.726, а также AAC-кадры, разбитые на несколько RTP-пакетов — [#14](https://github.com/OpenIPC/decoder/issues/14)
+> - **Не поддерживается звук G.726** — [#14](https://github.com/OpenIPC/decoder/issues/14)
 > - **Возможная зависимость от сервисов Google (GAPPS)** на некоторых устройствах; изучается, поэтому отключайте GAPPS осознанно — [#15](https://github.com/OpenIPC/decoder/issues/15)
 > - **Логин и пароль хранятся и передаются в открытом виде** (RTSP/HTTP без шифрования; Basic отправляется, если камера не запросила Digest) — [#16](https://github.com/OpenIPC/decoder/issues/16)
 >

diff --git a/README.zh-CN.md b/README.zh-CN.md
@@ -34,7 +34,7 @@
 ## 功能
 
 - **视频：** RTSP 播放，通过 MediaCodec 进行 H.264/H.265 硬件解码
-- **音频：** AAC（RFC 3640 `mpeg4-generic`、ADTS）、G.711 μ-law/A-law、L16 PCM（单声道/立体声）
+- **音频：** AAC（RFC 3640 `mpeg4-generic`、ADTS、MP4A-LATM）、Opus、G.711 μ-law/A-law、L16 PCM（单声道/立体声）
 - **显示：** 单路画面，或 Quad 四分屏（同时显示 4 路摄像机）
 - **操作：** 双指缩放、拖动平移、双击复位，支持 Android TV 遥控器（Leanback 启动器）
 - **网络：** 支持 Basic 和 Digest 认证、RTSP 保活，断线后自动重连（指数退避），连接质量指示
@@ -93,7 +93,7 @@
 >
 > - **仅支持 RTSP over TCP**，不支持 UDP 和组播 — [#7](https://github.com/OpenIPC/decoder/issues/7)
 > - **仅有 4 个摄像机槽位** — [#13](https://github.com/OpenIPC/decoder/issues/13)
-> - **不支持的音频格式：** MP4A-LATM、Opus、G.726，以及跨多个 RTP 包分片的 AAC 帧 — [#14](https://github.com/OpenIPC/decoder/issues/14)
+> - **不支持 G.726 音频** — [#14](https://github.com/OpenIPC/decoder/issues/14)
 > - **部分设备上可能依赖 Google 服务（GAPPS）**，仍在调查中，请谨慎禁用 GAPPS — [#15](https://github.com/OpenIPC/decoder/issues/15)
 > - **用户名和密码以明文存储和传输**（未加密的 RTSP/HTTP；摄像机未要求 Digest 时发送 Basic） — [#16](https://github.com/OpenIPC/decoder/issues/16)
 >

diff --git a/android/app/src/main/java/com/openipc/decoder/AudioConfig.java b/android/app/src/main/java/com/openipc/decoder/AudioConfig.java
@@ -13,6 +13,8 @@ class AudioConfig {
     static final String PCMU = "PCMU"; // G.711 mu-law
     static final String PCMA = "PCMA"; // G.711 A-law
     static final String AAC  = "AAC";
+    static final String LATM = "LATM"; // MP4A-LATM (RFC 6416): AAC in LATM framing
+    static final String OPUS = "OPUS";
 
     String codec = NONE;
     int pt = -1;
@@ -26,6 +28,8 @@ class AudioConfig {
     int sizeLength;
     int indexLength;
     int indexDeltaLength;
+    // MP4A-LATM: "cpresent=1" puts the configuration in-band, which is not supported
+    boolean latmConfigInBand;
 
     /** Fill defaults for static RTP payload types (RFC 3551), which may come without rtpmap. */
     void applyStaticPayloadType() {
@@ -46,6 +50,10 @@ void applyRtpmap(String encoding) {
         bigEndian = false;
         if (name.equals("MPEG4-GENERIC") || name.equals("AAC") || name.equals("MP4A")) {
             codec = AAC;
+        } else if (name.equals("MP4A-LATM")) {
+            codec = LATM;
+        } else if (name.equals("OPUS")) {
+            codec = OPUS;
         } else if (name.equals("PCMU")) {
             codec = PCMU;
         } else if (name.equals("PCMA")) {
@@ -54,7 +62,7 @@ void applyRtpmap(String encoding) {
             codec = PCM;
             bigEndian = true;
         } else {
-            // MP4A-LATM, OPUS, G726, ... are not supported
+            // G.726 and others are not supported
             codec = NONE;
         }
 
@@ -86,6 +94,7 @@ void applyFmtp(String params) {
                     case "sizelength":       sizeLength = Integer.parseInt(value); break;
                     case "indexlength":      indexLength = Integer.parseInt(value); break;
                     case "indexdeltalength": indexDeltaLength = Integer.parseInt(value); break;
+                    case "cpresent":         latmConfigInBand = !"0".equals(value); break;
                     default: break;
                 }
             } catch (NumberFormatException ignored) {}
@@ -102,6 +111,96 @@ void finish() {
                 || indexDeltaLength < 0 || indexDeltaLength > 16)) {
             codec = NONE;
         }
+        if (OPUS.equals(codec)) {
+            // RFC 7587: always 48 kHz and "/2" in rtpmap; the decoder handles mono streams too
+            sampleRate = 48000;
+            channels = 2;
+        }
+        if (LATM.equals(codec)) {
+            // fmtp config= is a StreamMuxConfig here; turn it into an AudioSpecificConfig
+            byte[] asc = latmConfigInBand || aacConfig == null ? null : latmToAsc(aacConfig);
+            if (asc == null) {
+                codec = NONE;
+            } else {
+                int[] info = ascInfo(asc);
+                if (info == null) {
+                    codec = NONE;
+                } else {
+                    aacConfig = asc;
+                    sampleRate = info[0];
+                    channels = info[1];
+                }
+            }
+        }
+    }
+
+    private static final int[] AAC_RATES = {
+            96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050,
+            16000, 12000, 11025, 8000, 7350
+    };
+
+    /**
+     * StreamMuxConfig to a 2-byte AudioSpecificConfig, or null unless it is the one layout
+     * the RTP path handles: audioMuxVersion 0, all streams same time framing, one subframe,
+     * one program, one layer, AAC-LC, a standard sampling rate, mono or stereo,
+     * frameLengthType 0 (byte-aligned PayloadLengthInfo), no other data and no CRC.
+     */
+    static byte[] latmToAsc(byte[] smc) {
+        BitReader r = new BitReader(smc);
+        if (r.bits(1) != 0) return null;  // audioMuxVersion 1
+        if (r.bits(1) != 1) return null;  // allStreamsSameTimeFraming
+        if (r.bits(6) != 0) return null;  // numSubFrames: exactly one
+        if (r.bits(4) != 0) return null;  // numProgram: exactly one
+        if (r.bits(3) != 0) return null;  // numLayer: exactly one
+        // AudioSpecificConfig
+        int objectType = r.bits(5);
+        int freqIndex = r.bits(4);
+        int channelConfig = r.bits(4);
+        if (objectType != 2) return null;                       // AAC-LC only (decoder profile)
+        if (freqIndex >= AAC_RATES.length) return null;         // reserved / explicit rate
+        if (channelConfig < 1 || channelConfig > 2) return null; // playback is mono/stereo
+        // GASpecificConfig
+        // The 2-byte ASC built below carries neither setting, so streams using them are refused
+        if (r.bits(1) != 0) return null;                        // frameLengthFlag: 960 samples
+        if (r.bits(1) != 0) return null;                        // dependsOnCoreCoder
+        if (r.bits(1) != 0) return null;                        // extensionFlag
+        // Back in StreamMuxConfig
+        if (r.bits(3) != 0) return null;  // frameLengthType 0: PayloadLengthInfo in bytes
+        r.bits(8);                         // latmBufferFullness
+        if (r.bits(1) != 0) return null;  // otherDataPresent
+        if (r.bits(1) != 0) return null;  // crcCheckPresent
+        if (r.overrun()) return null;
+        return new byte[] {
+                (byte) ((objectType << 3) | (freqIndex >> 1)),
+                (byte) (((freqIndex & 1) << 7) | (channelConfig << 3))
+        };
+    }
+
+    /** {sample rate, channels} of a 2-byte AudioSpecificConfig, or null. */
+    static int[] ascInfo(byte[] asc) {
+        if (asc == null || asc.length < 2) return null;
+        int freqIndex = ((asc[0] & 0x07) << 1) | ((asc[1] & 0x80) >> 7);
+        int channelConfig = (asc[1] & 0x78) >> 3;
+        if (freqIndex >= AAC_RATES.length || channelConfig < 1 || channelConfig > 2) return null;
+        return new int[] {AAC_RATES[freqIndex], channelConfig};
+    }
+
+    private static final class BitReader {
+        private final byte[] data;
+        private int pos;
+
+        BitReader(byte[] data) { this.data = data; }
+
+        int bits(int n) {
+            int v = 0;
+            for (int i = 0; i < n; i++, pos++) {
+                int bit = pos >> 3 < data.length ? (data[pos >> 3] >> (7 - (pos & 7))) & 1 : 0;
+                v = (v << 1) | bit;
+            }
+            return v;
+        }
+
+        boolean overrun() { return pos > data.length * 8; }
     }
 
     private static byte[] parseHex(String hex) {