* Fix segment error when start pcm with channel=2 for the first time.

Author: lxowalle

components/voice/port/maixcam/maix_audio_mmf.cpp

@@ -228,13 +228,36 @@ namespace maix::audio
         param->path = path;
         param->block = block;
         uint32_t pcm_flag = PCM_IN | (!param->block ? PCM_NONBLOCK : 0);
+#ifdef PLATFORM_MAIXCAM
+        // Fix segment error when start pcm with channel=2 for the first time.
+        if (channel != 1) {
+            config.channels = 1;
+            config.rate = 16000;
+            param->pcm = pcm_open(param->card, param->device, pcm_flag, &config);
+            if (param->pcm == NULL) {
+                err::check_null_raise(param->pcm, "failed to allocate memory for PCM");
+            } else if (!pcm_is_ready(param->pcm)){
+                pcm_close(param->pcm);
+                err::check_raise(err::ERR_RUNTIME, "failed to open PCM");
+            }
+            pcm_prepare(param->pcm);
+            pcm_start(param->pcm);
+            pcm_close(param->pcm);
+            config.channels = (uint32_t)channel;
+            config.rate = (uint32_t)sample_rate;
+        }
+#endif
         param->pcm = pcm_open(param->card, param->device, pcm_flag, &config);
         if (param->pcm == NULL) {
             err::check_null_raise(param->pcm, "failed to allocate memory for PCM");
         } else if (!pcm_is_ready(param->pcm)){
             pcm_close(param->pcm);
             err::check_raise(err::ERR_RUNTIME, "failed to open PCM");
         }
+        if (param->block) {
+            pcm_prepare(param->pcm);
+        }
+
         _param = param;
     }
 

examples/audio_demo/main/src/main.cpp

@@ -532,7 +532,7 @@ int _main(int argc, char* argv[])
         err::check_bool_raise(r.format() == format);
         err::check_bool_raise(r.channel() == channel);
 
-        log::info("Record over!\r\n");
+        log::info("Record start\r\n");
         auto bytes_per_frame = r.frame_size();
         while (!app::need_exit()) {
             auto t = time::ticks_ms();