@@ -147,6 +147,7 @@ typedef struct HLSContext {

     HLSSegment *old_segments;

     char *basename;

+    char *base_output_dirname;

     char *vtt_basename;

     char *vtt_m3u8_name;

     char *baseurl;

@@ -584,7 +585,7 @@ static int hls_mux_init(AVFormatContext *s)

     if (hls->segment_type == SEGMENT_TYPE_FMP4) {

         hls->fmp4_init_mode = 1;

-        if ((ret = s->io_open(s, &oc->pb, hls->fmp4_init_filename, AVIO_FLAG_WRITE, NULL)) < 0) {

+        if ((ret = s->io_open(s, &oc->pb, hls->base_output_dirname, AVIO_FLAG_WRITE, NULL)) < 0) {

             av_log(s, AV_LOG_ERROR, "Failed to open segment '%s'\n", hls->fmp4_init_filename);

             return ret;

         }

@@ -1286,14 +1287,19 @@ fail:

     return err;

 }

-static const char * get_default_pattern_localtime_fmt(void)

+static const char * get_default_pattern_localtime_fmt(AVFormatContext *s)

 {

     char b[21];

     time_t t = time(NULL);

     struct tm *p, tmbuf;

+    HLSContext *hls = s->priv_data;

+

     p = localtime_r(&t, &tmbuf);

     // no %s support when strftime returned error or left format string unchanged

     // also no %s support on MSVC, which invokes the invalid parameter handler on unsupported format strings, instead of returning an error

+    if (hls->segment_type == SEGMENT_TYPE_FMP4) {

+        return (HAVE_LIBC_MSVCRT || !strftime(b, sizeof(b), "%s", p) || !strcmp(b, "%s")) ? "-%Y%m%d%H%M%S.m4s" : "-%s.m4s";

+    }

     return (HAVE_LIBC_MSVCRT || !strftime(b, sizeof(b), "%s", p) || !strcmp(b, "%s")) ? "-%Y%m%d%H%M%S.ts" : "-%s.ts";

 }

@@ -1303,16 +1309,19 @@ static int hls_write_header(AVFormatContext *s)

     int ret, i;

     char *p;

     const char *pattern = "%d.ts";

-    const char *pattern_localtime_fmt = get_default_pattern_localtime_fmt();

+    const char *pattern_localtime_fmt = get_default_pattern_localtime_fmt(s);

     const char *vtt_pattern = "%d.vtt";

     AVDictionary *options = NULL;

     int byterange_mode = (hls->flags & HLS_SINGLE_FILE) || (hls->max_seg_size > 0);

     int basename_size;

     int vtt_basename_size;

-    if (hls->segment_type == SEGMENT_TYPE_FMP4 && byterange_mode) {

-        av_log(s, AV_LOG_WARNING, "Have not support fmp4 byterange mode yet now\n");

-        return AVERROR_PATCHWELCOME;

+    if (hls->segment_type == SEGMENT_TYPE_FMP4) {

+        if (byterange_mode) {

+            av_log(s, AV_LOG_WARNING, "Have not support fmp4 byterange mode yet now\n");

+            return AVERROR_PATCHWELCOME;

+        }

+        pattern = "%d.m4s";

     }

     if ((hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_SECONDS_SINCE_EPOCH) ||

         (hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_FORMATTED_DATETIME)) {

@@ -1412,6 +1421,31 @@ static int hls_write_header(AVFormatContext *s)

         } else {

             av_strlcat(hls->basename, pattern, basename_size);

         }

+

+        if (av_strcasecmp(hls->fmp4_init_filename, "init.mp4")) {

+            int fmp4_init_filename_len = strlen(hls->fmp4_init_filename) + 1;

+            hls->base_output_dirname = av_malloc(fmp4_init_filename_len);

+            if (!hls->base_output_dirname) {

+                ret = AVERROR(ENOMEM);

+                goto fail;

+            }

+            av_strlcpy(hls->base_output_dirname, hls->fmp4_init_filename, fmp4_init_filename_len);

+        } else {

+            hls->base_output_dirname = av_malloc(basename_size);

+            if (!hls->base_output_dirname) {

+                ret = AVERROR(ENOMEM);

+                goto fail;

+            }

+

+            av_strlcpy(hls->base_output_dirname, s->filename, basename_size);

+            p = strrchr(hls->base_output_dirname, '/');

+            if (p) {

+                *(p + 1) = '\0';

+                av_strlcat(hls->base_output_dirname, hls->fmp4_init_filename, basename_size);

+            } else {

+                av_strlcpy(hls->base_output_dirname, hls->fmp4_init_filename, basename_size);

+            }

+        }

     }

     if (!hls->use_localtime) {

         ret = sls_flag_check_duration_size_index(hls);

@@ -1686,6 +1720,7 @@ static int hls_write_trailer(struct AVFormatContext *s)

         ff_format_io_close(s, &vtt_oc->pb);

     }

     av_freep(&hls->basename);

+    av_freep(&hls->base_output_dirname);

     av_freep(&hls->key_basename);

     avformat_free_context(oc);