avformat/hlsenc: check fragment size plus start_pos large than hls_segment_size

if vs->size + vs->start_pos > hls->max_seg_size, should split segment.

Signed-off-by: Steven Liu <lq@chinaffmpeg.org>

libavformat/hlsenc.c

@@ -2390,7 +2390,7 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
                                       && (hls->flags & HLS_TEMP_FILE);
             }
 
-            if ((hls->max_seg_size > 0 && (vs->size >= hls->max_seg_size)) || !byterange_mode) {
+            if ((hls->max_seg_size > 0 && (vs->size + vs->start_pos >= hls->max_seg_size)) || !byterange_mode) {
                 AVDictionary *options = NULL;
                 char *filename = NULL;
                 if (hls->key_info_file || hls->encrypt) {
@@ -2485,14 +2485,15 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
         if (hls->flags & HLS_SINGLE_FILE) {
             vs->start_pos += vs->size;
         } else if (hls->max_seg_size > 0) {
-            vs->start_pos = new_start_pos;
-            if (vs->size >= hls->max_seg_size) {
+            if (vs->size + vs->start_pos >= hls->max_seg_size) {
                 vs->sequence++;
                 sls_flag_file_rename(hls, vs, old_filename);
                 ret = hls_start(s, vs);
                 vs->start_pos = 0;
                 /* When split segment by byte, the duration is short than hls_time,
                  * so it is not enough one segment duration as hls_time, */
+            } else {
+                vs->start_pos = new_start_pos;
             }
         } else {
             vs->start_pos = new_start_pos;