@@ -273,6 +273,10 @@ ffmpeg -i in.nut -hls_flags single_file out.m3u8

 @end example

 Will produce the playlist, @file{out.m3u8}, and a single segment file,

 @file{out.ts}.

+

+@item hls_flags delete_segments

+Segment files removed from the playlist are deleted after a period of time

+equal to the duration of the segment plus the duration of the playlist.

 @end table

 @anchor{ico}

@@ -19,8 +19,12 @@

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */

+#include "config.h"

 #include <float.h>

 #include <stdint.h>

+#if HAVE_UNISTD_H

+#include <unistd.h>

+#endif

 #include "libavutil/avassert.h"

 #include "libavutil/mathematics.h"

@@ -31,6 +35,7 @@

 #include "avformat.h"

 #include "internal.h"

+#include "os_support.h"

 typedef struct HLSSegment {

     char filename[1024];

@@ -44,6 +49,7 @@ typedef struct HLSSegment {

 typedef enum HLSFlags {

     // Generate a single media file and use byte ranges in the playlist.

     HLS_SINGLE_FILE = (1 << 0),

+    HLS_DELETE_SEGMENTS = (1 << 1),

 } HLSFlags;

 typedef struct HLSContext {

@@ -73,6 +79,7 @@ typedef struct HLSContext {

     HLSSegment *segments;

     HLSSegment *last_segment;

+    HLSSegment *old_segments;

     char *basename;

     char *baseurl;

@@ -82,6 +89,71 @@ typedef struct HLSContext {

     AVIOContext *pb;

 } HLSContext;

+static int hls_delete_old_segments(HLSContext *hls) {

+

+    HLSSegment *segment, *previous_segment = NULL;

+    float playlist_duration = 0.0f;

+    int ret = 0, path_size;

+    char *dirname = NULL, *p, *path;

+

+    segment = hls->segments;

+    while (segment) {

+        playlist_duration += segment->duration;

+        segment = segment->next;

+    }

+

+    segment = hls->old_segments;

+    while (segment) {

+        playlist_duration -= segment->duration;

+        previous_segment = segment;

+        segment = previous_segment->next;

+        if (playlist_duration <= -previous_segment->duration) {

+            previous_segment->next = NULL;

+            break;

+        }

+    }

+

+    if (segment) {

+        if (hls->segment_filename) {

+            dirname = av_strdup(hls->segment_filename);

+        } else {

+            dirname = av_strdup(hls->avf->filename);

+        }

+        if (!dirname) {

+            ret = AVERROR(ENOMEM);

+            goto fail;

+        }

+        p = (char *)av_basename(dirname);

+        *p = '\0';

+    }

+

+    while (segment) {

+        av_log(hls, AV_LOG_DEBUG, "deleting old segment %s\n",

+                                  segment->filename);

+        path_size = strlen(dirname) + strlen(segment->filename) + 1;

+        path = av_malloc(path_size);

+        if (!path) {

+            ret = AVERROR(ENOMEM);

+            goto fail;

+        }

+        av_strlcpy(path, dirname, path_size);

+        av_strlcat(path, segment->filename, path_size);

+        if (unlink(path) < 0) {

+            av_log(hls, AV_LOG_ERROR, "failed to delete old segment %s: %s\n",

+                                     path, strerror(errno));

+        }

+        av_free(path);

+        previous_segment = segment;

+        segment = previous_segment->next;

+        av_free(previous_segment);

+    }

+

+fail:

+    av_free(dirname);

+

+    return ret;

+}

+

 static int hls_mux_init(AVFormatContext *s)

 {

     HLSContext *hls = s->priv_data;

@@ -116,6 +188,7 @@ static int hls_append_segment(HLSContext *hls, double duration, int64_t pos,

                               int64_t size)

 {

     HLSSegment *en = av_malloc(sizeof(*en));

+    int ret;

     if (!en)

         return AVERROR(ENOMEM);

@@ -137,7 +210,14 @@ static int hls_append_segment(HLSContext *hls, double duration, int64_t pos,

     if (hls->max_nb_segments && hls->nb_entries >= hls->max_nb_segments) {

         en = hls->segments;

         hls->segments = en->next;

-        av_free(en);

+        if (en && hls->flags & HLS_DELETE_SEGMENTS &&

+                !(hls->flags & HLS_SINGLE_FILE || hls->wrap)) {

+            en->next = hls->old_segments;

+            hls->old_segments = en;

+            if ((ret = hls_delete_old_segments(hls)) < 0)

+                return ret;

+        } else

+            av_free(en);

     } else

         hls->nb_entries++;

@@ -146,9 +226,9 @@ static int hls_append_segment(HLSContext *hls, double duration, int64_t pos,

     return 0;

 }

-static void hls_free_segments(HLSContext *hls)

+static void hls_free_segments(HLSSegment *p)

 {

-    HLSSegment *p = hls->segments, *en;

+    HLSSegment *en;

     while(p) {

         en = p;

@@ -402,7 +482,8 @@ static int hls_write_trailer(struct AVFormatContext *s)

     hls->avf = NULL;

     hls_window(s, 1);

-    hls_free_segments(hls);

+    hls_free_segments(hls->segments);

+    hls_free_segments(hls->old_segments);

     avio_close(hls->pb);

     return 0;

 }

@@ -420,6 +501,7 @@ static const AVOption options[] = {

     {"hls_segment_filename", "filename template for segment files", OFFSET(segment_filename),   AV_OPT_TYPE_STRING, {.str = NULL},            0,       0,         E},

     {"hls_flags",     "set flags affecting HLS playlist and media file generation", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E, "flags"},

     {"single_file",   "generate a single media file indexed with byte ranges", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E, "flags"},

+    {"delete_segments", "delete segment files that are no longer part of the playlist", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_DELETE_SEGMENTS }, 0, UINT_MAX,   E, "flags"},

     { NULL },

 };