+/**
+ * Insert a fake onMetadata packet into the FLV stream to notify the FLV
+ * demuxer about the duration of the stream.
+ *
+ * This should only be done if there was no real onMetadata packet sent by the
+ * server at the start of the stream and if we were able to retrieve a valid
+ * duration via a getStreamLength call.
+ *
+ * @return 0 for successful operation, negative value in case of error
+ */
+static int inject_fake_duration_metadata(RTMPContext *rt)
+{
+ // We need to insert the metdata packet directly after the FLV
+ // header, i.e. we need to move all other already read data by the
+ // size of our fake metadata packet.
+
+ uint8_t* p;
+ // Keep old flv_data pointer
+ uint8_t* old_flv_data = rt->flv_data;
+ // Allocate a new flv_data pointer with enough space for the additional package
+ if (!(rt->flv_data = av_malloc(rt->flv_size + 55))) {
+ rt->flv_data = old_flv_data;
+ return AVERROR(ENOMEM);
+ }
+
+ // Copy FLV header
+ memcpy(rt->flv_data, old_flv_data, 13);
+ // Copy remaining packets
+ memcpy(rt->flv_data + 13 + 55, old_flv_data + 13, rt->flv_size - 13);
+ // Increase the size by the injected packet
+ rt->flv_size += 55;
+ // Delete the old FLV data
+ av_free(old_flv_data);
+
+ p = rt->flv_data + 13;
+ bytestream_put_byte(&p, FLV_TAG_TYPE_META);
+ bytestream_put_be24(&p, 40); // size of data part (sum of all parts below)
+ bytestream_put_be24(&p, 0); // timestamp
+ bytestream_put_be32(&p, 0); // reserved
+
+ // first event name as a string
+ bytestream_put_byte(&p, AMF_DATA_TYPE_STRING);
+ // "onMetaData" as AMF string
+ bytestream_put_be16(&p, 10);
+ bytestream_put_buffer(&p, "onMetaData", 10);
+
+ // mixed array (hash) with size and string/type/data tuples
+ bytestream_put_byte(&p, AMF_DATA_TYPE_MIXEDARRAY);
+ bytestream_put_be32(&p, 1); // metadata_count
+
+ // "duration" as AMF string
+ bytestream_put_be16(&p, 8);
+ bytestream_put_buffer(&p, "duration", 8);
+ bytestream_put_byte(&p, AMF_DATA_TYPE_NUMBER);
+ bytestream_put_be64(&p, av_double2int(rt->duration));
+
+ // Finalise object
+ bytestream_put_be16(&p, 0); // Empty string
+ bytestream_put_byte(&p, AMF_END_OF_OBJECT);
+ bytestream_put_be32(&p, 40); // size of data part (sum of all parts below)
+
+ return 0;
+}
+