diff --git a/libavformat/rtmppkt.c b/libavformat/rtmppkt.c
index 81621b1a99..fb3726bdd3 100644
--- a/libavformat/rtmppkt.c
+++ b/libavformat/rtmppkt.c
@@ -169,6 +169,7 @@ static int rtmp_packet_read_one_chunk(URLContext *h, RTMPPacket *p,
 
     uint8_t buf[16];
     int channel_id, timestamp, size;
+    uint32_t ts_field; // non-extended timestamp or delta field
     uint32_t extra = 0;
     enum RTMPPacketType type;
     int written = 0;
@@ -195,12 +196,12 @@ static int rtmp_packet_read_one_chunk(URLContext *h, RTMPPacket *p,
 
     hdr >>= 6;
     if (hdr == RTMP_PS_ONEBYTE) {
-        timestamp = prev_pkt[channel_id].ts_delta;
+        ts_field = prev_pkt[channel_id].ts_delta;
     } else {
         if (ffurl_read_complete(h, buf, 3) != 3)
             return AVERROR(EIO);
         written += 3;
-        timestamp = AV_RB24(buf);
+        ts_field = AV_RB24(buf);
         if (hdr != RTMP_PS_FOURBYTES) {
             if (ffurl_read_complete(h, buf, 3) != 3)
                 return AVERROR(EIO);
@@ -217,11 +218,13 @@ static int rtmp_packet_read_one_chunk(URLContext *h, RTMPPacket *p,
                 extra = AV_RL32(buf);
             }
         }
-        if (timestamp == 0xFFFFFF) {
-            if (ffurl_read_complete(h, buf, 4) != 4)
-                return AVERROR(EIO);
-            timestamp = AV_RB32(buf);
-        }
+    }
+    if (ts_field == 0xFFFFFF) {
+        if (ffurl_read_complete(h, buf, 4) != 4)
+            return AVERROR(EIO);
+        timestamp = AV_RB32(buf);
+    } else {
+        timestamp = ts_field;
     }
     if (hdr != RTMP_PS_TWELVEBYTES)
         timestamp += prev_pkt[channel_id].timestamp;
@@ -232,8 +235,7 @@ static int rtmp_packet_read_one_chunk(URLContext *h, RTMPPacket *p,
             return ret;
         p->read = written;
         p->offset = 0;
-        prev_pkt[channel_id].ts_delta   = timestamp -
-                                          prev_pkt[channel_id].timestamp;
+        prev_pkt[channel_id].ts_delta   = ts_field;
         prev_pkt[channel_id].timestamp  = timestamp;
     } else {
         // previous packet in this channel hasn't completed reading
diff --git a/libavformat/rtmppkt.h b/libavformat/rtmppkt.h
index 7121d7e268..3ccc6b4110 100644
--- a/libavformat/rtmppkt.h
+++ b/libavformat/rtmppkt.h
@@ -78,7 +78,7 @@ typedef struct RTMPPacket {
     int            channel_id; ///< RTMP channel ID (nothing to do with audio/video channels though)
     RTMPPacketType type;       ///< packet payload type
     uint32_t       timestamp;  ///< packet full timestamp
-    uint32_t       ts_delta;   ///< timestamp increment to the previous one in milliseconds (latter only for media packets)
+    uint32_t       ts_delta;   ///< 24-bit timestamp or increment to the previous one, in milliseconds (latter only for media packets). Clipped to a maximum of 0xFFFFFF, indicating an extended timestamp field.
     uint32_t       extra;      ///< probably an additional channel ID used during streaming data
     uint8_t        *data;      ///< packet payload
     int            size;       ///< packet payload size