diff --git a/src/mp4/moof.c b/src/mp4/moof.c
index abd7a98..ede03a6 100644
--- a/src/mp4/moof.c
+++ b/src/mp4/moof.c
@@ -277,11 +277,11 @@ enum BufError write_trun(
 
     err = put_u8(ptr, 0);
     chk_err; // 1 version
-    const bool data_offset_present = true;
-    const bool first_sample_flags_present = false;
-    const bool sample_duration_present = true;
-    const bool sample_size_present = true;
-    const bool sample_flags_present = true;
+    bool data_offset_present = true;
+    bool first_sample_flags_present = false;
+    bool sample_duration_present = !is_audio;
+    bool sample_size_present = !is_audio;
+    bool sample_flags_present = !is_audio;
     {
         uint64_t flags = 0x0;
         if (data_offset_present) {
@@ -319,7 +319,7 @@ enum BufError write_trun(
         err = put_i32_be(ptr, 0);
         chk_err; // 4 fake data_offset
     }
-
+    
     if (first_sample_flags_present) {
         err = put_u32_be(ptr, is_audio ? 0 : 33554432);
         chk_err; // 4 first_sample_flags
diff --git a/src/mp4/moov.c b/src/mp4/moov.c
index bca9f15..af1e3d7 100644
--- a/src/mp4/moov.c
+++ b/src/mp4/moov.c
@@ -720,10 +720,10 @@ enum BufError write_ObjectDescriptor(struct BitBuf *ptr, const struct MoovInfo *
     chk_err; // flags
     err = write_DecoderConfig(ptr, moov_info);
     chk_err;
-    err = write_TagAudioSpecificConfig(ptr, moov_info);
-    chk_err;
     err = write_SLConfigDescriptor(ptr);
     chk_err;
+    err = write_TagAudioSpecificConfig(ptr, moov_info);
+    chk_err;
     err = put_u32_le_to_offset(ptr, var_len, varint32(ptr->offset - var_len - 4));
     chk_err;
     return BUF_OK;
diff --git a/src/mp4/mp4.c b/src/mp4/mp4.c
index 0281e56..e38bb3c 100644
--- a/src/mp4/mp4.c
+++ b/src/mp4/mp4.c
@@ -99,20 +99,17 @@ enum BufError mp4_set_slice(const char *nal_data, const uint32_t nal_len,
     char is_iframe) {
     enum BufError err;
 
-    const uint32_t samples_info_len = 1;
-    struct SampleInfo samples_info[2];
+    struct SampleInfo samples_info[9];
     memset(samples_info, 0, sizeof(samples_info));
     samples_info[0].size = nal_len + 4; // add size of sample
     samples_info[0].duration = default_sample_size;
     samples_info[0].flags = is_iframe ? 0 : 65536;
     samples_info[1].size = buf_aud.offset;
-    samples_info[1].duration = 40000.f * 
-        (buf_aud.offset / (aud_bitrate * 25 / 6.f));
 
     buf_moof.offset = 0;
     err = write_moof(
         &buf_moof, 0, 0, 0, default_sample_size, samples_info,
-        samples_info_len, samples_info + 1, 1);
+        1, samples_info + 1, buf_aud.offset / aud_framesize);
     chk_err;
 
     buf_mdat.offset = 0;