diff --git a/src/Makefile.am b/src/Makefile.am
index c617421b..02b95172 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -67,6 +67,8 @@ utun_CORE_SOURCES = \
 	media_async/media_async.c \
 	media_async/attachment.c \
 	media_async/attachment.h \
+	media_async/voice_file.c \
+	media_async/voice_file.h \
 	video/video.c \
 	transport_layer/dummynet.c \
 	ntp_time.c \
@@ -181,6 +183,8 @@ libutun_a_SOURCES = \
 	media_async/media_async.c \
 	media_async/attachment.c \
 	media_async/attachment.h \
+	media_async/voice_file.c \
+	media_async/voice_file.h \
 	video/video.c \
 	transport_layer/dummynet.c \
 	ntp_time.c \
diff --git a/src/media_async/voice_file.c b/src/media_async/voice_file.c
index 12c88527..29b8ab10 100644
--- a/src/media_async/voice_file.c
+++ b/src/media_async/voice_file.c
@@ -10,7 +10,8 @@ int voice_file_encode(const int16_t* pcm, size_t count, int rate, int channels,
                        const char* path, struct attachment_info* info) {
     static const int bitrates[] = {16000, 32000, 64000}, complexities[] = {2, 5, 10};
     static const char levels[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-    if (!pcm || !info || !path || rate <= 0 || (channels != 1 && channels != 2) || preset < 0 || preset > 2) goto invalid;
+    if (!pcm || !info || !path || (rate != 8000 && rate != 12000 && rate != 16000 && rate != 24000 && rate != 48000) ||
+        (channels != 1 && channels != 2) || preset < 0 || preset > 2) goto invalid;
     size_t frame = (size_t)(rate / 50) * channels, samples = count / frame * frame;
     if (samples < (size_t)rate * channels / 2 || samples / channels / rate > 86400) goto invalid;
     opus_codec_encoder_t* encoder = opus_codec_encoder_create(rate, channels);
@@ -52,7 +53,7 @@ done:
     opus_codec_encoder_destroy(encoder);
     if (error) {
         DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "voice_file: encoding/write failed path=%s", path);
-        if (remove(path)) DEBUG_WARN(DEBUG_CATEGORY_MEDIA, "voice_file: partial file cleanup failed path=%s", path);
+        if (file && remove(path)) DEBUG_WARN(DEBUG_CATEGORY_MEDIA, "voice_file: partial file cleanup failed path=%s", path);
     } else DEBUG_INFO(DEBUG_CATEGORY_MEDIA, "voice_file: prepared path=%s duration=%ums rate=%d channels=%d", path, info->duration_ms, rate, channels);
     return error;
 invalid: