Distinguishing sync/non-sync MP4 samples, handling disabled audio tracks

Author: wberube

src/app_config.c

@@ -444,8 +444,8 @@ enum ConfigError parse_app_config(void) {
     parse_bool(&ini, "stream", "enable", &app_config.stream_enable);
     if (app_config.stream_enable) {
         int count, val;
-        parse_int(&ini, "stream", "udp_srcport", 0, USHRT_MAX, &val);
-        if (err != CONFIG_OK) app_config.stream_udp_srcport = (unsigned short)val;
+        err = parse_int(&ini, "stream", "udp_srcport", 0, USHRT_MAX, &val);
+        if (err == CONFIG_OK) app_config.stream_udp_srcport = (unsigned short)val;
         parse_list(&ini, "stream", "dest",
             sizeof(app_config.stream_dests) / sizeof(*app_config.stream_dests),
             &count, app_config.stream_dests);

src/fmt/moof.c

@@ -315,7 +315,8 @@ enum BufError write_trun(
     }
 
     if (first_sample_flags_present) {
-        err = put_u32_be(ptr, is_audio ? 0 : 33554432);
+        err = put_u32_be(ptr, is_audio ? 0x02000000 :
+            (samples_info[0].flags == 0 ? 0x02000000 : 0x01010000));
         chk_err; // 4 first_sample_flags
     }
     for (uint32_t i = 0; i < samples_info_count; ++i) {

src/fmt/mp4.c

@@ -89,7 +89,7 @@ void mp4_set_vps(const char *nal_data, const uint32_t nal_len) {
 
 enum BufError mp4_set_slice(const char *nal_data, const uint32_t nal_len,
     char is_iframe) {
-    uint64_t aud_ticks;
+    uint64_t aud_ticks = 0;
     enum BufError err;
 
     struct SampleInfo samples_info[2];
@@ -98,12 +98,15 @@ enum BufError mp4_set_slice(const char *nal_data, const uint32_t nal_len,
     samples_info[0].duration = default_sample_size;
     samples_info[0].flags = is_iframe ? 0 : 65536;
     samples_info[1].size = buf_aud.offset;
-    if (aud_bitrate > 0)
+    if (aud_bitrate > 0 && buf_aud.offset > 0) {
         aud_ticks = ((uint64_t)(buf_aud.offset << 3) * timescale) /
             (aud_bitrate * 1000);
-    samples_info[1].duration = (uint32_t)aud_ticks;
-    last_fragment_duration =
-        MAX(samples_info[1].duration, samples_info[0].duration);
+        samples_info[1].duration = (uint32_t)aud_ticks;
+        last_fragment_duration = MAX(samples_info[1].duration, samples_info[0].duration);
+    } else {
+        samples_info[1].duration = 0;
+        last_fragment_duration = samples_info[0].duration;
+    }
 
     buf_moof.offset = 0;
     err = write_moof(