# HG changeset patch
# User Sergey Kandaurov <pluknet@nginx.com>
# Date 1395669310 -14400
# Node ID a23c35496c2fc0ba9a34d968c2ca6d1f9374f8a8
# Parent  345e4fd4bb64f1b3ad48a20b69f62bcd39a443c9
Mp4: skipped empty stss atom table in output.

The atom may have no data entries after cropping.

This fixes "zero size buf in output" alerts.

diff --git a/src/http/modules/ngx_http_mp4_module.c b/src/http/modules/ngx_http_mp4_module.c
--- a/src/http/modules/ngx_http_mp4_module.c
+++ b/src/http/modules/ngx_http_mp4_module.c
@@ -2273,16 +2273,21 @@ ngx_http_mp4_update_stss_atom(ngx_http_m
     ngx_http_mp4_crop_stss_data(mp4, trak, 1);
     ngx_http_mp4_crop_stss_data(mp4, trak, 0);
 
-    entry = (uint32_t *) data->pos;
-    end = (uint32_t *) data->last;
-
-    start_sample = trak->start_sample;
-
-    while (entry < end) {
-        sample = ngx_mp4_get_32value(entry);
-        sample -= start_sample;
-        ngx_mp4_set_32value(entry, sample);
-        entry++;
+    if (trak->sync_samples_entries) {
+        entry = (uint32_t *) data->pos;
+        end = (uint32_t *) data->last;
+
+        start_sample = trak->start_sample;
+
+        while (entry < end) {
+            sample = ngx_mp4_get_32value(entry);
+            sample -= start_sample;
+            ngx_mp4_set_32value(entry, sample);
+            entry++;
+        }
+
+    } else {
+        trak->out[NGX_HTTP_MP4_STSS_DATA].buf = NULL;
     }
 
     atom_size = sizeof(ngx_http_mp4_stss_atom_t) + (data->last - data->pos);