{"id":52,"date":"2026-05-03T06:37:59","date_gmt":"2026-05-03T06:37:59","guid":{"rendered":"http:\/\/www.fryduck99.com\/index.php\/2026\/05\/03\/android-audiotrack-%e5%9c%a8%e8%bd%a6%e8%bd%bd%e5%b9%b3%e5%8f%b0%e4%b8%8a%e7%9a%84%e5%8e%9f%e7%90%86%e3%80%81%e9%97%ae%e9%a2%98%e4%b8%8e%e8%b0%83%e8%af%95\/"},"modified":"2026-05-03T07:07:44","modified_gmt":"2026-05-03T07:07:44","slug":"android-audiotrack-car-platform","status":"publish","type":"post","link":"\/index.php\/2026\/05\/03\/android-audiotrack-car-platform\/","title":{"rendered":"Android AudioTrack \u5728\u8f66\u8f7d\u5e73\u53f0\u4e0a\u7684\u539f\u7406\u3001\u95ee\u9898\u4e0e\u8c03\u8bd5"},"content":{"rendered":"<p>&gt; \u9002\u7528\u5e73\u53f0\uff1aAndroid Automotive OS (AAOS)<\/p>\n<p>&gt; \u9002\u7528\u7248\u672c\uff1aAndroid 14 \/ 15 \/ 16<\/p>\n<p>&gt; \u6ce8\uff1aAndroid 17 \u6e90\u7801\u5c1a\u672a\u516c\u5f00\uff0c\u6682\u4e0d\u6d89\u53ca<\/p>\n<h2>\u4e00\u3001AudioTrack \u5728\u8f66\u8f7d\u97f3\u9891\u67b6\u6784\u4e2d\u7684\u4f4d\u7f6e<\/h2>\n<h3>1.1 \u6574\u4f53\u67b6\u6784<\/h3>\n<p>\u8f66\u8f7d Android \u7684\u97f3\u9891\u8def\u5f84\u6bd4\u666e\u901a Android \u590d\u6742\u5f97\u591a\uff0c\u65b0\u589e\u4e86 CarAudioService \u4f5c\u4e3a\u4e2d\u95f4\u5c42\uff1a<\/p>\n<pre><code>\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502                        \u5e94\u7528\u5c42 (App)                         \u2502\n\u2502              AudioTrack.write() \/ AAudio                   \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n                             \u2502  JNI\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u25bc\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502                 Native AudioTrack (C++)                    \u2502\n\u2502            frameworks\/av\/media\/libmedia\/                   \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n                             \u2502  Binder IPC\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u25bc\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502                    CarAudioService                          \u2502\n\u2502         (CarAudioManager \/ AudioZone \/ AudioFocus)         \u2502\n\u2502              frameworks\/av\/services\/car\/                     \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n                             \u2502\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u25bc\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502                     AudioFlinger                            \u2502\n\u2502              (PlaybackThread \/ MixerThread)                \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n                             \u2502\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u25bc\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502                      CarAudioHAL                            \u2502\n\u2502          (\u8f66\u8f7d\u529f\u653e \/ DSP \/ \u591a\u533a\u57df\u8def\u7531\u7ba1\u7406)                   \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n                             \u2502\n                    \u8f66\u8f7d\u786c\u4ef6\uff08\u626c\u58f0\u5668 \/ \u529f\u653e \/ DSP\uff09\n<\/code><\/pre>\n<p><\/p>\n<p><strong>\u5173\u952e\u533a\u522b<\/strong>\uff1a<\/p>\n<ul>\n<li>\u666e\u901a Android\uff1aApp \u2192 AudioFlinger \u2192 HAL \u2192 \u786c\u4ef6<\/li>\n<li>\u8f66\u8f7d Android\uff1aApp \u2192 CarAudioService \u2192 AudioFlinger \u2192 CarAudioHAL \u2192 \u786c\u4ef6<\/li>\n<\/ul>\n<h3>1.2 \u5171\u4eab\u5185\u5b58\u673a\u5236\uff08\u4e0e\u666e\u901a Android \u76f8\u540c\uff09<\/h3>\n<p>AudioTrack \u4e0e AudioFlinger \u4e4b\u95f4\u901a\u8fc7 mmap \u5171\u4eab\u5185\u5b58\u4f20\u8f93\u6570\u636e\uff0c\u4e0d\u62f7\u8d1d\uff1a<\/p>\n<pre><code>\n\/\/ audio_track_cblk_t \u2014 \u6838\u5fc3\u63a7\u5236\u7ed3\u6784\nstruct audio_track_cblk_t {\n    volatile uint32_t server;    \/\/ AudioFlinger \u5df2\u6d88\u8d39\u5230\u7684\u5e27\u4f4d\u7f6e\n    volatile uint32_t user;      \/\/ App \u5df2\u5199\u5165\u7684\u5e27\u4f4d\u7f6e\n    uint32_t bufferEnd;          \/\/ \u7f13\u51b2\u533a\u672b\u5c3e\u5e27\u7d22\u5f15\n    void*    buffers;           \/\/ \u5171\u4eab\u5185\u5b58\u6570\u636e\u533a\n};\n<\/code><\/pre>\n<p><\/p>\n<p>App \u5199\u6570\u636e\u65f6\u66f4\u65b0 <code>user<\/code>\uff0cAudioFlinger \u6d88\u8d39\u65f6\u66f4\u65b0 <code>server<\/code>\u3002<code>user - server<\/code> \u5373\u4e3a\u7f13\u51b2\u533a\u4e2d\u5c1a\u672a\u88ab\u6d88\u8d39\u7684\u6570\u636e\u91cf\u3002<\/p>\n<h2>\u4e8c\u3001\u8f66\u8f7d\u591a\u533a\u57df\u97f3\u9891\uff08Audio Zone\uff09<\/h2>\n<h3>2.1 \u4e3a\u4ec0\u4e48\u9700\u8981\u5206\u533a<\/h3>\n<p>\u8f66\u662f\u4e00\u4e2a\u591a\u4eba\u5171\u5904\u7684\u7a7a\u95f4\uff0c\u4e0d\u540c\u5ea7\u4f4d\u7684\u4e58\u5ba2\u9700\u8981\u72ec\u7acb\u7684\u97f3\u9891\u63a7\u5236\uff1a<\/p>\n<pre><code>\n\u251c\u2500\u2500 \u9a7e\u9a76\u5ea7\u533a\u57df\uff08Driver Zone, Zone 0\uff09\n\u2502   \u251c\u2500\u2500 \u626c\u58f0\u5668\uff1a\u901a\u5e38\u4f4d\u4e8e\u524d\u95e8 + \u4eea\u8868\u53f0\u4e2d\u592e\n\u2502   \u251c\u2500\u2500 \u5178\u578b\u7528\u9014\uff1a\u5bfc\u822a\u64ad\u62a5\u3001\u4eea\u8868\u76d8\u63d0\u793a\u97f3\n\u2502   \u2514\u2500\u2500 \u7279\u70b9\uff1a\u5b89\u5168\u76f8\u5173\u4f18\u5148\u7ea7\u6700\u9ad8\n\u2502\n\u251c\u2500\u2500 \u526f\u9a7e\u533a\u57df\uff08Front Passenger Zone, Zone 1\uff09\n\u2502   \u251c\u2500\u2500 \u626c\u58f0\u5668\uff1a\u524d\u95e8\n\u2502   \u2514\u2500\u2500 \u5178\u578b\u7528\u9014\uff1a\u526f\u9a7e\u5a31\u4e50\n\u2502\n\u251c\u2500\u2500 \u540e\u6392\u5de6\u4fa7 \/ \u53f3\u4fa7\uff08rear left \/ right\uff09\n\u2502   \u2514\u2500\u2500 \u5404\u6709\u72ec\u7acb\u97f3\u91cf\u63a7\u5236\n\u2502\n\u2514\u2500\u2500 \u4e2d\u592e\u901a\u9053\uff08Center Channel\uff09\n    \u2514\u2500\u2500 \u5bfc\u822a\u8bed\u97f3\u52a9\u624b\u3001ADAS \u8b66\u793a\u97f3\u4e13\u5c5e\n<\/code><\/pre>\n<p><\/p>\n<h3>2.2 \u58f0\u97f3\u7c7b\u578b\u4e0e\u4f18\u5148\u7ea7<\/h3>\n<p>\u8f66\u673a\u4e0a\u540c\u65f6\u5b58\u5728\u591a\u4e2a\u97f3\u9891\u6d41\u7ade\u4e89\u64ad\u653e\uff0cAudioFlinger \u7684 Mixer \u6309\u4ee5\u4e0b\u4f18\u5148\u7ea7\u6df7\u5408\uff1a<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>\u4f18\u5148\u7ea7<\/td>\n<td>\u58f0\u97f3\u7c7b\u578b<\/td>\n<td>\u8bf4\u660e<\/td>\n<\/tr>\n<\/table>\n<p>|&#8212;&#8212;&#8211;|&#8212;&#8212;&#8212;|&#8212;&#8212;|<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>**\u6700\u9ad8**<\/td>\n<td>ADAS \u8b66\u793a\u97f3\uff08\u78b0\u649e\u9884\u8b66\u3001\u8f66\u9053\u504f\u79bb\uff09<\/td>\n<td>\u5fc5\u987b\u7acb\u5373\u62a2\u5360\uff0cFLAG_AUDIBILITY_ENFORCED<\/td>\n<\/tr>\n<tr>\n<td>**\u9ad8**<\/td>\n<td>\u5bfc\u822a\u64ad\u62a5<\/td>\n<td>\u6b21\u9ad8\u4f18\u5148\u7ea7<\/td>\n<\/tr>\n<tr>\n<td>**\u9ad8**<\/td>\n<td>\u514d\u63d0\u7535\u8bdd\uff08\u4e0b\u884c\uff09<\/td>\n<td>\u901a\u8bdd\u65f6\u538b\u5236\u5a92\u4f53<\/td>\n<\/tr>\n<tr>\n<td>**\u4e2d**<\/td>\n<td>\u8bed\u97f3\u52a9\u624b \/ \u5524\u9192\u8bcd<\/td>\n<td>\u9700\u8981\u6301\u7eed\u76d1\u542c<\/td>\n<\/tr>\n<tr>\n<td>**\u4f4e**<\/td>\n<td>\u5a92\u4f53\u97f3\u4e50<\/td>\n<td>\u53ef\u88ab\u9ad8\u4f18\u5148\u7ea7\u58f0\u97f3\u6253\u65ad<\/td>\n<\/tr>\n<\/table>\n<pre><code>\n\/\/ \u6b63\u786e\u7684\u8f66\u8f7d AudioTrack \u521b\u5efa\u65b9\u5f0f\nAudioAttributes attrs = new AudioAttributes.Builder()\n    .setUsage(AudioUsage.Voice)          \/\/ \u8bed\u97f3\u7c7b\u7528\u9014\n    .setSource(AudioSource.VoiceCall)    \/\/ \u6765\u6e90\u662f\u901a\u8bdd\n    .setFlags(AudioAttributes.FLAG_AUDIBILITY_ENFORCED) \/\/ \u5b89\u5168\u8b66\u793a\u97f3\u5fc5\u52a0\n    .build();\n\nAudioTrack track = new AudioTrack.Builder()\n    .setAudioAttributes(attrs)\n    .setAudioZoneId(0)                   \/\/ \u7ed1\u5b9a\u5230\u9a7e\u9a76\u533a\n    .setBufferSizeInBytes(8192)\n    .build();\n<\/code><\/pre>\n<p><\/p>\n<h2>\u4e09\u3001\u7f13\u51b2\u533a\u7ba1\u7406\u4e0e Underrun \/ Overrun<\/h2>\n<h3>3.1 \u4ec0\u4e48\u662f Underrun\uff08\u6b20\u8f7d\uff09<\/h3>\n<p>Underrun \u53d1\u751f\u5728 AudioFlinger \u6d88\u8d39\u6570\u636e\u7684\u901f\u5ea6\u5927\u4e8e App \u751f\u4ea7\u6570\u636e\u7684\u901f\u5ea6\u65f6\uff1a<\/p>\n<pre><code>\n\u65f6\u95f4\u8f74 \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u25ba\n\n\u65f6\u523bA: [##############........]  75% \u6ee1\uff0c\u6b63\u5e38\u64ad\u653e\n\u65f6\u523bB: [--------------------]  0% \u7a7a\uff0cAudioFlinger \u65e0\u6570\u636e \u2192 \u9759\u97f3\n                                      \u2191\n                                  \u8fd9\u91cc\u4ea7\u751f\u9759\u97f3\n                                  \u6062\u590d\u77ac\u95f4 \u2192 Pop \u97f3\n<\/code><\/pre>\n<p><\/p>\n<p><strong>\u6839\u672c\u539f\u56e0<\/strong>\uff1a<\/p>\n<p>1. App \u5c42 <code>write()<\/code> \u592a\u6162\uff08\u4e3b\u7ebf\u7a0b\u88ab GC\u3001CPU \u62a2\u5360\u7b49\uff09<\/p>\n<p>2. \u7f13\u51b2\u533a\u8bbe\u7f6e\u592a\u5c0f<\/p>\n<p>3. AudioFlinger \u7684 PlaybackThread \u88ab\u9ad8\u4f18\u5148\u7ea7\u7ebf\u7a0b\u62a2\u5360<\/p>\n<p>4. HAL \u5c42\u7f13\u51b2\u8fc7\u5927\uff0c\u7cfb\u7edf\u6574\u4f53&#8221;\u751f\u4ea7-\u6d88\u8d39&#8221;\u8282\u594f\u88ab\u6253\u4e71<\/p>\n<h3>3.2 \u4ec0\u4e48\u662f Overrun\uff08\u8fc7\u8f7d\uff09<\/h3>\n<p>Overrun \u4e0e underrun \u76f8\u53cd\uff0cApp \u5199\u5165\u901f\u5ea6\u8fc7\u5feb\uff0c<code>write()<\/code> \u957f\u65f6\u95f4\u963b\u585e\u5728\u7f13\u51b2\u533a\u6ee1\u7684\u72b6\u6001\uff1a<\/p>\n<pre><code>\nadb logcat | grep \"AudioTrack\"\n# \u770b\u5230 \"write() blocked for > 50ms\" \u8fd9\u7c7b log\uff0c\u8bf4\u660e\u6b63\u5728 Overrun\n<\/code><\/pre>\n<p><\/p>\n<h3>3.3 Pop \u97f3\uff08\u7206\u7834\u97f3\uff09\u7684\u6765\u6e90<\/h3>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>\u6765\u6e90<\/td>\n<td>\u89e6\u53d1\u573a\u666f<\/td>\n<td>\u6839\u56e0<\/td>\n<\/tr>\n<\/table>\n<p>|&#8212;&#8212;|&#8212;&#8212;&#8212;|&#8212;&#8212;|<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>**Underrun \u6062\u590d**<\/td>\n<td>\u7f13\u51b2\u533a\u6e05\u7a7a\u540e\u7b2c\u4e00\u6b21\u6062\u590d\u64ad\u653e<\/td>\n<td>\u5171\u4eab\u5185\u5b58\u672a\u521d\u59cb\u5316 \/ DAC \u6ca1\u6709 fade-in<\/td>\n<\/tr>\n<tr>\n<td>**HAL \u7b2c\u4e00\u5e27**<\/td>\n<td>\u6bcf\u6b21\u64ad\u653e\u7ebf\u7a0b\u542f\u52a8\u65f6<\/td>\n<td>HAL \u5c42\u9a71\u52a8\u6ca1\u6709\u5728\u7b2c\u4e00\u5e27\u505a\u6e05\u96f6<\/td>\n<\/tr>\n<tr>\n<td>**\u6253\u65ad-\u6062\u590d**<\/td>\n<td>\u5bfc\u822a\u64ad\u62a5\u6253\u65ad \u2192 \u6062\u590d\u5a92\u4f53<\/td>\n<td>\u6062\u590d\u77ac\u95f4\u7f13\u51b2\u533a\u72b6\u6001\u4e0e\u505c\u6b62\u524d\u4e0d\u4e00\u81f4<\/td>\n<\/tr>\n<tr>\n<td>**\u542f\u505c\uff08Start-Stop\uff09**<\/td>\n<td>\u53d1\u52a8\u673a\u542f\u505c\u7cfb\u7edf\u7184\u706b\/\u91cd\u542f\u65f6<\/td>\n<td>DAC \u7535\u6e90\u5e8f\u5217\u4e0d\u5bf9\uff0cI2S \u91cd\u65b0\u521d\u59cb\u5316<\/td>\n<\/tr>\n<tr>\n<td>**\u91c7\u6837\u7387\u5207\u6362**<\/td>\n<td>\u4ece 44.1kHz \u5207\u6362\u5230 48kHz<\/td>\n<td>\u91cd\u91c7\u6837\u5668\u521d\u59cb\u9636\u6bb5\u8f93\u51fa\u7a81\u53d8<\/td>\n<\/tr>\n<\/table>\n<p><strong>Android 16 \u5bf9\u542f\u505c\u573a\u666f\u505a\u4e86\u4fee\u590d<\/strong>\uff0c\u8981\u6c42 HAL \u5b9e\u73b0\u5fc5\u987b\u505a fade-in\/fade-out\uff0c\u907f\u514d\u7535\u6e90\u6ce2\u52a8\u5bfc\u81f4\u7684 Pop\u3002<\/p>\n<h3>3.4 \u7f13\u51b2\u533a\u5927\u5c0f\u53c2\u8003<\/h3>\n<p>\u4ee5 48kHz \u53cc\u58f0\u9053 16bit PCM \u4e3a\u4f8b\uff1a<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>bufferSizeInBytes<\/td>\n<td>\u5e27\u6570<\/td>\n<td>\u7f13\u51b2\u65f6\u957f<\/td>\n<td>\u9002\u7528\u573a\u666f<\/td>\n<\/tr>\n<\/table>\n<p>|&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;|&#8212;&#8212;|&#8212;&#8212;&#8212;|&#8212;&#8212;&#8212;|<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>2048<\/td>\n<td>512 \u5e27<\/td>\n<td>~10ms<\/td>\n<td>\u8d85\u4f4e\u5ef6\u8fdf\uff0c\u4f46 underrun \u98ce\u9669\u9ad8<\/td>\n<\/tr>\n<tr>\n<td>4096<\/td>\n<td>1024 \u5e27<\/td>\n<td>~21ms<\/td>\n<td>\u4f4e\u5ef6\u8fdf\u573a\u666f<\/td>\n<\/tr>\n<tr>\n<td>8192<\/td>\n<td>2048 \u5e27<\/td>\n<td>~42ms<\/td>\n<td>\u5e73\u8861\u4e4b\u9009\uff0c\u9002\u5408\u5927\u591a\u6570\u573a\u666f<\/td>\n<\/tr>\n<tr>\n<td>16384<\/td>\n<td>4096 \u5e27<\/td>\n<td>~85ms<\/td>\n<td>\u9ad8\u7a33\u5b9a\u6027\uff0c\u5ef6\u8fdf\u4e0d\u654f\u611f\u573a\u666f<\/td>\n<\/tr>\n<\/table>\n<h2>\u56db\u3001\u8f66\u8f7d\u97f3\u9891\u5ef6\u8fdf\u5206\u6790<\/h2>\n<h3>4.1 \u7aef\u5230\u7aef\u5ef6\u8fdf\u6784\u6210<\/h3>\n<pre><code>\n\u603b\u5ef6\u8fdf = T_app + T_buffer + T_mixer + T_hal + T_dac\n<\/code><\/pre>\n<p><\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>\u9636\u6bb5<\/td>\n<td>\u8bf4\u660e<\/td>\n<td>\u5178\u578b\u5ef6\u8fdf<\/td>\n<\/tr>\n<\/table>\n<p>|&#8212;&#8212;|&#8212;&#8212;|&#8212;&#8212;&#8212;|<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>**T_app**<\/td>\n<td>App \u7684 write() \u8c03\u7528\u8fd4\u56de\u65f6\u95f4<\/td>\n<td>1-5ms<\/td>\n<\/tr>\n<tr>\n<td>**T_buffer**<\/td>\n<td>\u6570\u636e\u5728 AudioTrack \u7f13\u51b2\u533a\u548c Mixer \u7f13\u51b2\u533a\u7684\u6392\u961f\u65f6\u95f4<\/td>\n<td>\u53d8\u91cf\uff0c10-100ms<\/td>\n<\/tr>\n<tr>\n<td>**T_mixer**<\/td>\n<td>PlaybackThread \u6df7\u97f3\/\u91cd\u91c7\u6837<\/td>\n<td>5-20ms<\/td>\n<\/tr>\n<\/table>\n<p>| <strong>T_hal<\/strong> | CarAudioHAL \u5185\u90e8\u7f13\u51b2 | 5-30ms\uff08\u53d6\u51b3\u4e8e\u5382\u5546\u5b9e\u73b0\uff09|<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>**T_dac**<\/td>\n<td>I2S\/PCM \u5230\u626c\u58f0\u5668<\/td>\n<td>1-5ms<\/td>\n<\/tr>\n<\/table>\n<p><strong>T_buffer \u662f\u6700\u5927\u7684\u4e0d\u786e\u5b9a\u56e0\u7d20<\/strong>\uff0c\u4e5f\u662f\u8f66\u8f7d\u97f3\u9891\u5ef6\u8fdf\u7684\u4e3b\u8981\u74f6\u9888\u3002<\/p>\n<h3>4.2 \u8f66\u8f7d\u573a\u666f\u7684\u5ef6\u8fdf\u8981\u6c42<\/h3>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>\u573a\u666f<\/td>\n<td>\u53ef\u63a5\u53d7\u5ef6\u8fdf<\/td>\n<td>\u8bf4\u660e<\/td>\n<\/tr>\n<\/table>\n<p>|&#8212;&#8212;|&#8212;&#8212;&#8212;&#8211;|&#8212;&#8212;|<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>**\u666e\u901a\u97f3\u4e50\u64ad\u653e**<\/td>\n<td>50-150ms<\/td>\n<td>\u4f53\u9a8c\u4e0d\u53d7\u5f71\u54cd<\/td>\n<\/tr>\n<tr>\n<td>**\u5bfc\u822a\u64ad\u62a5**<\/td>\n<td>< 100ms<\/td>\n<td>\u518d\u9ad8\u4f1a\u6709\u660e\u663e\u6ede\u540e\u611f<\/td>\n<\/tr>\n<tr>\n<td>**\u5361\u62c9OK \/ \u5b9e\u65f6\u76d1\u542c**<\/td>\n<td>< 30ms<\/td>\n<td>\u4eba\u8033\u80fd\u611f\u77e5 20ms \u4ee5\u4e0a\u7684\u6ede\u540e<\/td>\n<\/tr>\n<tr>\n<td>**ADAS \u8b66\u793a\u97f3**<\/td>\n<td>< 50ms<\/td>\n<td>\u5b89\u5168\u76f8\u5173\uff0c\u4f46\u4e0d\u9700\u8981\u6781\u4f4e\u5ef6\u8fdf<\/td>\n<\/tr>\n<\/table>\n<h3>4.3 \u964d\u4f4e\u5ef6\u8fdf\u7684\u65b9\u6cd5<\/h3>\n<p>#### \u65b9\u6cd5\u4e00\uff1a\u4f7f\u7528\u4f4e\u5ef6\u8fdf\u6807\u5fd7<\/p>\n<pre><code>\nAudioAttributes attrs = new AudioAttributes.Builder()\n    .setUsage(AudioUsage.Game)  \/\/ \u6216 Greeting \/ Sonification\n    .setFlags(AudioAttributes.FLAG_LOW_LATENCY)\n    .build();\n<\/code><\/pre>\n<p><\/p>\n<p><code>FLAG_LOW_LATENCY<\/code> \u4f1a\u8ba9 CarAudioService \u8bf7\u6c42 AudioFlinger \u4f7f\u7528\u66f4\u5c0f\u7684\u7f13\u51b2\u533a\u3002\u4f46\u5b9e\u9645\u6548\u679c\u53d6\u51b3\u4e8e HAL \u5382\u5546\u5b9e\u73b0\uff0c\u5f88\u591a\u8f66\u8f7d HAL \u5185\u90e8\u7f13\u51b2\u533a\u65e0\u6cd5\u8fdb\u4e00\u6b65\u7f29\u5c0f\u3002<\/p>\n<p>#### \u65b9\u6cd5\u4e8c\uff1a\u7ed5\u8fc7 Mixer\uff08\u76f4\u8fde HAL\uff0cAndroid 15+\uff09<\/p>\n<p>Android 15 \u5f15\u5165\u4e86\u76f4\u8fde HAL \u8def\u5f84\uff0c\u7ed5\u8fc7 MixerThread\uff0c\u51cf\u5c11\u8c03\u5ea6\u5f00\u9500\uff1a<\/p>\n<pre><code>\n\/\/ \u8bf7\u6c42\u72ec\u5360\u8f93\u51fa\u8def\u5f84\ntrack.setPreferredAudioClientUid(Process.SYSTEM_UID);\n<\/code><\/pre>\n<p><\/p>\n<p>#### \u65b9\u6cd5\u4e09\uff1a\u4f7f\u7528 AAudio<\/p>\n<p>AAudio \u662f\u6bd4 AudioTrack \u66f4\u8f7b\u91cf\u7684 API\uff0c\u8bbe\u8ba1\u76ee\u6807\u5c31\u662f\u4f4e\u5ef6\u8fdf\uff1a<\/p>\n<pre><code>\nAAudioStreamBuilder builder;\nAAudioStream *stream;\nAAudioStreamBuilder_setPerformanceMode(builder, AAUDIO_PERFORMANCE_MODE_LOW_LATENCY);\nAAudioStreamBuilder_openStream(builder, &stream);\n<\/code><\/pre>\n<p><\/p>\n<p>#### \u65b9\u6cd5\u56db\uff1a\u786c\u4ef6\u9009\u578b<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>\u65b9\u6848<\/td>\n<td>\u5ef6\u8fdf<\/td>\n<td>\u8bf4\u660e<\/td>\n<\/tr>\n<\/table>\n<p>|&#8212;&#8212;|&#8212;&#8212;|&#8212;&#8212;|<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>\u84dd\u7259 A2DP<\/td>\n<td>100-200ms<\/td>\n<td>**\u4e0d\u9002\u5408\u5361\u62c9OK \/ \u5b9e\u65f6\u76d1\u542c**<\/td>\n<\/tr>\n<tr>\n<td>3.5mm \u6a21\u62df\u8f93\u51fa<\/td>\n<td>\u4e2d\u7b49<\/td>\n<td>\u5185\u7f6e Codec \u901a\u5e38\u6709\u989d\u5916\u7f13\u51b2<\/td>\n<\/tr>\n<tr>\n<td>USB \u58f0\u5361<\/td>\n<td>\u4f4e<\/td>\n<td>\u63a8\u8350\u7528\u4e8e\u5361\u62c9OK\u7b49\u5b9e\u65f6\u573a\u666f<\/td>\n<\/tr>\n<tr>\n<td>\u8f66\u8f7d DSP \u76f4\u89e3<\/td>\n<td>\u6781\u4f4e<\/td>\n<td>\u4ee3\u4ef7\u662f\u67b6\u6784\u590d\u6742\uff0c\u9700\u5382\u5546\u914d\u5408<\/td>\n<\/tr>\n<\/table>\n<h2>\u4e94\u3001\u8f66\u8f7d\u7279\u6709\u7684\u95ee\u9898\u573a\u666f<\/h2>\n<h3>5.1 \u5bfc\u822a\u64ad\u62a5\u6253\u65ad\u5a92\u4f53 \u2192 Pop \u97f3<\/h3>\n<p><strong>\u573a\u666f<\/strong>\uff1a\u8f66\u4e3b\u6b63\u5728\u542c\u97f3\u4e50\uff0c\u5bfc\u822a\u8bf4&#8221;\u524d\u65b9500\u7c73\u53f3\u8f6c&#8221;\u2014\u2014\u5bfc\u822a\u64ad\u62a5\u62a2\u5360\u7126\u70b9\u540e\uff0c\u5a92\u4f53\u6062\u590d\u64ad\u653e\u65f6\u51fa\u73b0 Pop \u97f3\u3002<\/p>\n<p><strong>\u65f6\u5e8f\u5206\u6790<\/strong>\uff1a<\/p>\n<pre><code>\nT1: \u5bfc\u822a AudioTrack \u62a2\u5360\u7126\u70b9 \u2192 \u5a92\u4f53 track \u88ab\u5f3a\u5236 pause()\nT2: \u5bfc\u822a\u64ad\u62a5\u7ed3\u675f \u2192 \u5a92\u4f53 track \u6062\u590d play()\nT3: \u7f13\u51b2\u533a\u6b8b\u7559 T1 \u65f6\u523b\u7684\u65e7\u6570\u636e + HAL \u53ef\u80fd\u5df2\u91cd\u65b0\u521d\u59cb\u5316\n    \u2193\n    Pop \u97f3\u51fa\u73b0\n<\/code><\/pre>\n<p><\/p>\n<p><strong>\u8c03\u8bd5\u65b9\u6cd5<\/strong>\uff1a<\/p>\n<pre><code>\nadb shell dumpsys media.audio_flinger | grep -A 20 \"Media\"\n# \u770b underrun \u8ba1\u6570\u662f\u5426\u5728\u5bfc\u822a\u6253\u65ad\u540e\u98d9\u5347\n\nadb logcat | grep -E \"CarAudioService|AudioFocus|Navigation\"\n<\/code><\/pre>\n<p><\/p>\n<h3>5.2 \u514d\u63d0\u901a\u8bdd\u4e0e\u5a92\u4f53\u6df7\u97f3\u95ee\u9898<\/h3>\n<p><strong>\u573a\u666f<\/strong>\uff1a\u901a\u8bdd\u65f6\u97f3\u4e50\u5e94\u8be5\u6682\u505c\u6216\u964d\u6df7\uff08ducking\uff09\uff0c\u4f46\u67d0\u4e9b HAL \u5b9e\u73b0\u4e0d\u6b63\u786e\uff0c\u5bfc\u81f4\uff1a<\/p>\n<ul>\n<li>\u5bf9\u65b9\u542c\u5230\u4f60\u8f66\u91cc\u7684\u97f3\u4e50\u58f0<\/li>\n<li>\u901a\u8bdd\u7ed3\u675f\u540e\u5a92\u4f53\u6062\u590d\u65f6\u51fa\u73b0 Pop<\/li>\n<\/ul>\n<p><strong>\u6839\u56e0<\/strong>\uff1aAudio Focus \u673a\u5236\u548c HAL \u7684\u8def\u7531\u7b56\u7565\u6ca1\u6709\u6b63\u786e\u8054\u52a8\u3002<\/p>\n<h3>5.3 \u542f\u505c\uff08Start-Stop\uff09\u9020\u6210\u7684 Pop<\/h3>\n<p><strong>\u573a\u666f<\/strong>\uff1a\u7b49\u7ea2\u706f\u65f6\u53d1\u52a8\u673a\u542f\u505c\u7cfb\u7edf\u7184\u706b\uff0c\u7136\u540e\u91cd\u65b0\u542f\u52a8\u2014\u2014\u97f3\u9891\u7cfb\u7edf\u968f\u4e4b\u91cd\u542f\uff0cDAC \u7684 I2S \u603b\u7ebf\u91cd\u65b0\u521d\u59cb\u5316\uff0c\u4ea7\u751f Pop\u3002<\/p>\n<p><strong>\u4fee\u590d\u60c5\u51b5<\/strong>\uff1a<\/p>\n<ul>\n<li>Android 16 \u5df2\u6539\u8fdb\u4e86 Suspend\/Resume \u7684\u4fdd\u62a4\u673a\u5236<\/li>\n<li>\u8981\u6c42 HAL \u5b9e\u73b0\u5fc5\u987b\u505a fade-in\/fade-out<\/li>\n<li>\u5982\u679c\u4ecd\u6709\u95ee\u9898\uff0c\u5927\u6982\u7387\u662f HAL \u9a71\u52a8\u5c42\u6ca1\u6709\u6309\u89c4\u8303\u5b9e\u73b0<\/li>\n<\/ul>\n<h3>5.4 \u591a\u533a\u57df\u97f3\u91cf\u63a7\u5236\u5931\u6548<\/h3>\n<p><strong>\u573a\u666f<\/strong>\uff1a\u53f8\u673a\u8c03\u5927\u5bfc\u822a\u97f3\u91cf\uff0c\u540e\u6392\u4e58\u5ba2\u7684\u97f3\u4e50\u97f3\u91cf\u4e5f\u8ddf\u7740\u53d8\uff0c\u6216\u8005\u53cd\u4e4b\u3002<\/p>\n<p><strong>\u6839\u56e0<\/strong>\uff1aApp \u7684 AudioTrack \u6ca1\u6709\u6b63\u786e\u7ed1\u5b9a\u5230\u5bf9\u5e94\u7684 AudioZone\uff0c\u5bfc\u81f4\u97f3\u91cf\u88ab\u9519\u8bef\u5730\u8def\u7531\u5230\u4e86\u5168\u5c40\u63a7\u5236\u94fe\u8def\u4e0a\u3002<\/p>\n<p><strong>\u6b63\u786e\u505a\u6cd5<\/strong>\uff1a<\/p>\n<pre><code>\n\/\/ \u6bcf\u4e2a\u533a\u57df\u7684 App \u5e94\u8be5\u7ed1\u5b9a\u5230\u5bf9\u5e94 Zone\naudioZone = CarAudioManager.getAudioZone(CarAudioManager.ZONE_ID_DRIVER);\ntrack = audioZone.createTrack(audioAttributes, config, bufferSize, ...);\n<\/code><\/pre>\n<p><\/p>\n<h2>\u516d\u3001\u8c03\u8bd5\u65b9\u6cd5<\/h2>\n<h3>6.1 \u786e\u8ba4\u95ee\u9898\u8fb9\u754c<\/h3>\n<pre><code>\n\u7b2c\u4e00\u6b65\uff1a\u786e\u8ba4\u662f\u7cfb\u7edf\u95ee\u9898\u8fd8\u662f App \u95ee\u9898\n  \u2193\n\u7528\u7cfb\u7edf\u81ea\u5e26\u5e94\u7528\u6d4b\u8bd5\uff08\u97f3\u4e50\u64ad\u653e\u5668 \/ \u5bfc\u822a\uff09\n  \u7cfb\u7edf\u81ea\u5e26\u4e5f\u6709\u95ee\u9898 \u2192 \u7cfb\u7edf\u5c42\u95ee\u9898\uff08HAL \/ CarAudioService\uff09\n  \u53ea\u6709\u6211\u7684 App \u6709\u95ee\u9898 \u2192 App \u5c42\u95ee\u9898\n<\/code><\/pre>\n<p><\/p>\n<h3>6.2 CarAudioService \u548c AudioFlinger Dump<\/h3>\n<pre><code>\n# \u67e5\u770b\u8f66\u8f7d\u97f3\u9891\u670d\u52a1\u5168\u72b6\u6001\uff08\u6700\u91cd\u8981\uff09\nadb shell dumpsys car_audio_service\n\n# \u67e5\u770b AudioFlinger\uff08PlaybackThread \/ underrun \u8ba1\u6570\uff09\nadb shell dumpsys media.audio_flinger\n\n# \u8f93\u51fa\u5173\u952e\u5b57\u6bb5\u89e3\u8bfb\uff1a\n#   Underruns: N       \u2192 N > 0 = \u53d1\u751f\u8fc7 underrun\n#   Buffer size: X    \u2192 \u7f13\u51b2\u533a\u603b\u5927\u5c0f\n#   Latency: Y ms     \u2192 \u7aef\u5230\u7aef\u5ef6\u8fdf\n#   Sample rate: Z    \u2192 \u5f53\u524d\u91c7\u6837\u7387\n<\/code><\/pre>\n<p><\/p>\n<h3>6.3 Logcat \u8fc7\u6ee4<\/h3>\n<pre><code>\n# \u8fc7\u6ee4 AudioTrack \u76f8\u5173\nadb logcat | grep -E \"AudioTrack|AudioFlinger|PlaybackThread\"\n\n# \u8fc7\u6ee4 underrun \/ buffer \u76f8\u5173\nadb logcat | grep -i \"underrun|buffer|pop\"\n\n# \u8fc7\u6ee4 CarAudioService\uff08\u8f66\u8f7d\u4e13\u7528\uff09\nadb logcat | grep -E \"CarAudioService|AudioZone|AudioFocus|CarAudio\"\n\n# \u8fc7\u6ee4 HAL \u5c42\uff08\u786e\u8ba4\u95ee\u9898\u5728\u54ea\u4e00\u5c42\uff09\nadb logcat | grep -E \"audio_hw|StreamOut|output_stream_write\"\n<\/code><\/pre>\n<p><\/p>\n<h3>6.4 \u4ee3\u7801\u5c42\u52a0 dump<\/h3>\n<p>#### \u5728 App \u7684 write() \u524d\u540e\u52a0\u65f6\u95f4\u6233\uff1a<\/p>\n<pre><code>\nlong t0 = System.nanoTime();\nint written = track.write(buffer, buffer.length);\nlong t1 = System.nanoTime();\nLog.d(\"AudioDebug\", \"write \" + written + \" bytes, cost=\" + (t1-t0)\/1_000_000 + \"ms\");\n\n\/\/ \u5982\u679c write() \u8fd4\u56de\u8017\u65f6 > 20ms\uff0c\u8bf4\u660e App \u5c42\u751f\u4ea7\u901f\u5ea6\u662f\u74f6\u9888\n<\/code><\/pre>\n<p><\/p>\n<p>#### \u83b7\u53d6\u7f13\u51b2\u533a\u6d88\u8d39\u8fdb\u5ea6\uff08Android 14+\uff09\uff1a<\/p>\n<pre><code>\nif (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {\n    AudioTrack.Tracker tracker = track.getTracker();\n    \/\/ \u901a\u8fc7 tracker \u76d1\u63a7\u7f13\u51b2\u533a\u586b\u6ee1\u7a0b\u5ea6\n}\n<\/code><\/pre>\n<p><\/p>\n<h3>6.5 HAL \u5c42 PCM dump\uff08\u5b9a\u4f4d\u95ee\u9898\u5728\u54ea\u4e00\u5c42\uff09<\/h3>\n<p>\u9700\u8981 root \u6743\u9650\uff0c\u5728 HAL \u5c42\u52a0 dump\uff08\u4e34\u65f6\u4fee\u6539\uff09\uff1a<\/p>\n<pre><code>\n\/\/ \u4fee\u6539 hardware\/interfaces\/audio\/core\/all-versions\/default\/StreamOut.cpp\n\/\/ \u5728 write() \u51fd\u6570\u4e2d\uff1a\nFILE* fp = fopen(\"\/data\/vendor\/audio_hal_dump.pcm\", \"ab\");\nfwrite(buffer, 1, size, fp);\nfclose(fp);\n<\/code><\/pre>\n<p><\/p>\n<p><strong>\u5224\u65ad\u903b\u8f91<\/strong>\uff1a<\/p>\n<ul>\n<li>HAL dump \u6570\u636e\u6b63\u786e + App dump \u6570\u636e\u6b63\u786e \u2192 \u95ee\u9898\u5728\u9a71\u52a8 \/ \u786c\u4ef6<\/li>\n<li>HAL dump \u5168\u662f 0 \u6216\u9519\u8bef \u2192 \u95ee\u9898\u5728 AudioFlinger \u6216\u66f4\u4e0a\u5c42<\/li>\n<li>App dump \u672c\u8eab\u9519\u8bef \u2192 App \u4ee3\u7801\u7684\u95ee\u9898<\/li>\n<\/ul>\n<h3>6.6 systrace \u5206\u6790<\/h3>\n<pre><code>\npython systrace.py -a com.example.yourapp \\\n    -o trace.html \\\n    sched freq idle am wm audio binder_driver\n\n# \u5728 chrome:\/\/tracing \u6253\u5f00 trace \u6587\u4ef6\n# \u5173\u6ce8\uff1a\n#   - AudioTrack write() \u884c\u662f\u5426\u6709\u957f\u65f6\u95f4\u7a7a\u767d\uff08underrun\uff09\n#   - PlaybackThread \u662f\u5426\u9891\u7e41\u88ab\u9ad8\u4f18\u5148\u7ea7\u7ebf\u7a0b\u62a2\u5360\n#   - \u4e3b\u7ebf\u7a0b\u662f\u5426\u5728 write() \u4e0a\u957f\u65f6\u95f4\u963b\u585e\uff08CPU \u7ade\u4e89\uff09\n<\/code><\/pre>\n<p><\/p>\n<h3>6.7 \u5b8c\u6574\u8c03\u8bd5\u6e05\u5355<\/h3>\n<pre><code>\n\u2460 \u7528\u7cfb\u7edf App \u6d4b\u8bd5\uff0c\u786e\u8ba4\u662f\u7cfb\u7edf\u8fd8\u662f App \u95ee\u9898\n\n\u2461 adb shell dumpsys car_audio_service\n   \u2192 \u786e\u8ba4 Zone \u914d\u7f6e\u662f\u5426\u6b63\u786e\n   \u2192 \u786e\u8ba4 Audio Focus \u6301\u6709\u8005\n\n\u2462 adb shell dumpsys media.audio_flinger\n   \u2192 \u627e Underruns \u8ba1\u6570 > 0 \u7684 Track\n   \u2192 \u627e Latency \u8fc7\u5927\u7684 Track\n\n\u2463 adb logcat \u8fc7\u6ee4\n   \u2192 \u641c underrun \/ pop \/ AudioTrack \u76f8\u5173 tag\n\n\u2464 \u786e\u8ba4 bufferSizeInBytes\n   \u2192 < 4096 \u5bb9\u6613 underrun\uff0c\u5efa\u8bae \u2265 4096\n\n\u2465 \u786e\u8ba4\u91c7\u6837\u7387\u5339\u914d\n   \u2192 track.getSampleRate() vs \u97f3\u9891\u6e90\u91c7\u6837\u7387\n   \u2192 \u4e0d\u4e00\u81f4\u65f6\u770b log \u6709\u65e0\u91cd\u91c7\u6837\u8b66\u544a\n\n\u2466 \u6293 HAL dump\n   \u2192 \u5bf9\u6bd4 Framework \u5c42\u548c HAL \u5c42\u7684\u6570\u636e\u662f\u5426\u4e00\u81f4\n\n\u2467 systrace\n   \u2192 \u5206\u6790\u7ebf\u7a0b\u8c03\u5ea6\u662f\u5426\u62a2\u5360\u4e86 AudioFlinger\n\n\u2468 \u6d4b\u8bd5\u542f\u505c\u573a\u666f\n   \u2192 \u53d1\u52a8\u673a\u542f\u505c\u540e\u97f3\u9891\u662f\u5426\u6b63\u5e38\u6062\u590d\uff0c\u6709\u65e0 Pop\n\n\u2469 \u591a Zone \u6d4b\u8bd5\n   \u2192 \u786e\u8ba4\u97f3\u91cf\u63a7\u5236\u662f\u5426\u5728\u6b63\u786e\u7684 Zone \u751f\u6548\n<\/code><\/pre>\n<p><\/p>\n<h2>\u4e03\u3001\u603b\u7ed3<\/h2>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>\u7ef4\u5ea6<\/td>\n<td>\u8bf4\u660e<\/td>\n<\/tr>\n<\/table>\n<p>|------|------|<\/p>\n<table border=\"1\" cellpadding=\"8\" cellspacing=\"0\">\n<tr>\n<td>**\u67b6\u6784**<\/td>\n<td>\u8f66\u8f7d\u6bd4\u666e\u901a Android \u591a CarAudioService \u4e2d\u95f4\u5c42\uff0c\u8d1f\u8d23\u591a Zone \u548c Audio Focus<\/td>\n<\/tr>\n<tr>\n<td>**\u5ef6\u8fdf**<\/td>\n<td>\u6b63\u5e38\u573a\u666f 50-150ms \u53ef\u63a5\u53d7\uff1b\u5361\u62c9OK < 30ms \u9700\u8981 AAudio + FLAG_LOW_LATENCY + USB \u58f0\u5361<\/td>\n<\/tr>\n<tr>\n<td>**Pop \u97f3\u6839\u56e0**<\/td>\n<td>\u6700\u5e38\u89c1\u7684\u662f underrun \u6062\u590d + HAL \u5c42\u6ca1\u6709 fade-in\uff0c\u5176\u6b21\u662f\u542f\u505c\u573a\u666f HAL \u91cd\u521d\u59cb\u5316<\/td>\n<\/tr>\n<tr>\n<td>**\u591a Zone**<\/td>\n<td>App \u5fc5\u987b\u901a\u8fc7 `setAudioZoneId()` \u7ed1\u5b9a\u5230\u6b63\u786e Zone\uff0c\u5426\u5219\u97f3\u91cf\u63a7\u5236\u5931\u6548<\/td>\n<\/tr>\n<tr>\n<td>**\u8c03\u8bd5\u5165\u53e3**<\/td>\n<td>`dumpsys car_audio_service` + `dumpsys media.audio_flinger` + HAL \u5c42 dump \u914d\u5408\u4f7f\u7528<\/td>\n<\/tr>\n<\/table>\n<p>\u5982\u679c\u9047\u5230\u5177\u4f53\u95ee\u9898\uff0c\u53ef\u4ee5\u6309\u4ee5\u4e0b\u683c\u5f0f\u63cf\u8ff0\uff1a<\/p>\n<p>1. <strong>\u51fa\u73b0\u7684\u5177\u4f53\u573a\u666f<\/strong>\uff08\u64ad\u653e\u97f3\u4e50 \/ \u5bfc\u822a\u64ad\u62a5 \/ \u514d\u63d0\u901a\u8bdd \/ \u542f\u505c\u540e\uff09<\/p>\n<p>2. <strong>\u5177\u4f53\u8868\u73b0<\/strong>\uff08Pop \u97f3 \/ \u65e0\u58f0 \/ \u5ef6\u8fdf\u5927 \/ \u67d0\u4e2a Zone \u65e0\u58f0\uff09<\/p>\n<p>3. <strong>\u6240\u6709 App \u90fd\u6709\u95ee\u9898\u8fd8\u662f\u53ea\u6709\u4f60\u7684 App \u6709\u95ee\u9898<\/strong><\/p>\n<p>4. <strong>Android \u7248\u672c<\/strong>\uff0814 \/ 15 \/ 16\uff09<\/p>\n<p>5. <strong>\u80fd\u5426\u63d0\u4f9b <code>adb shell dumpsys car_audio_service<\/code> \u548c <code>adb shell dumpsys media.audio_flinger<\/code> \u7684\u5b8c\u6574\u8f93\u51fa<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>&gt; \u9002\u7528\u5e73\u53f0\uff1aAndroid Automotive OS (AAOS) &gt; \u9002\u7528\u7248\u672c\uff1aAndroi &#8230; <a title=\"Android AudioTrack \u5728\u8f66\u8f7d\u5e73\u53f0\u4e0a\u7684\u539f\u7406\u3001\u95ee\u9898\u4e0e\u8c03\u8bd5\" class=\"read-more\" href=\"\/index.php\/2026\/05\/03\/android-audiotrack-car-platform\/\" aria-label=\"\u9605\u8bfb Android AudioTrack \u5728\u8f66\u8f7d\u5e73\u53f0\u4e0a\u7684\u539f\u7406\u3001\u95ee\u9898\u4e0e\u8c03\u8bd5\">\u9605\u8bfb\u66f4\u591a<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,3],"tags":[],"class_list":["post-52","post","type-post","status-publish","format-standard","hentry","category-tech","category-car-audio"],"_links":{"self":[{"href":"\/index.php\/wp-json\/wp\/v2\/posts\/52","targetHints":{"allow":["GET"]}}],"collection":[{"href":"\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"\/index.php\/wp-json\/wp\/v2\/comments?post=52"}],"version-history":[{"count":3,"href":"\/index.php\/wp-json\/wp\/v2\/posts\/52\/revisions"}],"predecessor-version":[{"id":55,"href":"\/index.php\/wp-json\/wp\/v2\/posts\/52\/revisions\/55"}],"wp:attachment":[{"href":"\/index.php\/wp-json\/wp\/v2\/media?parent=52"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"\/index.php\/wp-json\/wp\/v2\/categories?post=52"},{"taxonomy":"post_tag","embeddable":true,"href":"\/index.php\/wp-json\/wp\/v2\/tags?post=52"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}