avformat/dashenc: Persistent HTTP connections supported as an option

Reviewed-by: Aman Gupta <aman@tmm1.net>
Reviewed-by: Steven Liu <lq@onvideo.cn>

doc/muxers.texi

@@ -249,6 +249,8 @@ DASH-templated name to used for the media segments. Default is "chunk-stream$Rep
 URL of the page that will return the UTC timestamp in ISO format. Example: "https://time.akamai.com/?iso"
 @item -http_user_agent @var{user_agent}
 Override User-Agent field in HTTP header. Applicable only for HTTP output.
+@item -http_persistent @var{http_persistent}
+Use persistent HTTP connections. Applicable only for HTTP output.
 @item -hls_playlist @var{hls_playlist}
 Generate HLS playlist files as well. The master playlist is generated with the filename master.m3u8.
 One media playlist file is generated for each stream with filenames media_0.m3u8, media_1.m3u8, etc.

libavformat/dashenc.c

@@ -37,6 +37,9 @@
 #include "avformat.h"
 #include "avio_internal.h"
 #include "hlsplaylist.h"
+#if CONFIG_HTTP_PROTOCOL
+#include "http.h"
+#endif
 #include "internal.h"
 #include "isom.h"
 #include "os_support.h"
@@ -103,7 +106,10 @@ typedef struct DASHContext {
     const char *utc_timing_url;
     const char *user_agent;
     int hls_playlist;
+    int http_persistent;
     int master_playlist_created;
+    AVIOContext *mpd_out;
+    AVIOContext *m3u8_out;
 } DASHContext;
 
 static struct codec_string {
@@ -117,6 +123,36 @@ static struct codec_string {
     { 0, NULL }
 };
 
+static int dashenc_io_open(AVFormatContext *s, AVIOContext **pb, char *filename,
+                           AVDictionary **options) {
+    DASHContext *c = s->priv_data;
+    int http_base_proto = filename ? ff_is_http_proto(filename) : 0;
+    int err = AVERROR_MUXER_NOT_FOUND;
+    if (!*pb || !http_base_proto || !c->http_persistent) {
+        err = s->io_open(s, pb, filename, AVIO_FLAG_WRITE, options);
+#if CONFIG_HTTP_PROTOCOL
+    } else {
+        URLContext *http_url_context = ffio_geturlcontext(*pb);
+        av_assert0(http_url_context);
+        err = ff_http_do_new_request(http_url_context, filename);
+#endif
+    }
+    return err;
+}
+
+static void dashenc_io_close(AVFormatContext *s, AVIOContext **pb, char *filename) {
+    DASHContext *c = s->priv_data;
+    int http_base_proto = filename ? ff_is_http_proto(filename) : 0;
+
+    if (!http_base_proto || !c->http_persistent) {
+        ff_format_io_close(s, pb);
+#if CONFIG_HTTP_PROTOCOL
+    } else {
+        avio_flush(*pb);
+#endif
+    }
+}
+
 static void set_codec_str(AVFormatContext *s, AVCodecParameters *par,
                           char *str, int size)
 {
@@ -218,6 +254,8 @@ static void set_http_options(AVDictionary **options, DASHContext *c)
 {
     if (c->user_agent)
         av_dict_set(options, "user_agent", c->user_agent, 0);
+    if (c->http_persistent)
+        av_dict_set_int(options, "multiple_requests", 1, 0);
 }
 
 static void get_hls_playlist_name(char *playlist_name, int string_size,
@@ -273,9 +311,10 @@ static void dash_free(AVFormatContext *s)
     av_freep(&c->streams);
 }
 
-static void output_segment_list(OutputStream *os, AVIOContext *out, DASHContext *c,
+static void output_segment_list(OutputStream *os, AVIOContext *out, AVFormatContext *s,
                                 int representation_id, int final)
 {
+    DASHContext *c = s->priv_data;
     int i, start_index = 0, start_number = 1;
     if (c->window_size) {
         start_index  = FFMAX(os->nb_segments   - c->window_size, 0);
@@ -339,7 +378,6 @@ static void output_segment_list(OutputStream *os, AVIOContext *out, DASHContext
         int timescale = os->ctx->streams[0]->time_base.den;
         char temp_filename_hls[1024];
         char filename_hls[1024];
-        AVIOContext *out_hls = NULL;
         AVDictionary *http_opts = NULL;
         int target_duration = 0;
         int ret = 0;
@@ -352,7 +390,7 @@ static void output_segment_list(OutputStream *os, AVIOContext *out, DASHContext
         snprintf(temp_filename_hls, sizeof(temp_filename_hls), use_rename ? "%s.tmp" : "%s", filename_hls);
 
         set_http_options(&http_opts, c);
-        avio_open2(&out_hls, temp_filename_hls, AVIO_FLAG_WRITE, NULL, &http_opts);
+        dashenc_io_open(s, &c->m3u8_out, temp_filename_hls, &http_opts);
         av_dict_free(&http_opts);
         for (i = start_index; i < os->nb_segments; i++) {
             Segment *seg = os->segments[i];
@@ -361,15 +399,15 @@ static void output_segment_list(OutputStream *os, AVIOContext *out, DASHContext
                 target_duration = lrint(duration);
         }
 
-        ff_hls_write_playlist_header(out_hls, 6, -1, target_duration,
+        ff_hls_write_playlist_header(c->m3u8_out, 6, -1, target_duration,
                                      start_number, PLAYLIST_TYPE_NONE);
 
-        ff_hls_write_init_file(out_hls, os->initfile, c->single_file,
+        ff_hls_write_init_file(c->m3u8_out, os->initfile, c->single_file,
                                os->init_range_length, os->init_start_pos);
 
         for (i = start_index; i < os->nb_segments; i++) {
             Segment *seg = os->segments[i];
-            ret = ff_hls_write_file_entry(out_hls, 0, c->single_file,
+            ret = ff_hls_write_file_entry(c->m3u8_out, 0, c->single_file,
                                     (double) seg->duration / timescale, 0,
                                     seg->range_length, seg->start_pos, NULL,
                                     c->single_file ? os->initfile : seg->file,
@@ -380,9 +418,10 @@ static void output_segment_list(OutputStream *os, AVIOContext *out, DASHContext
         }
 
         if (final)
-            ff_hls_write_end_list(out_hls);
+            ff_hls_write_end_list(c->m3u8_out);
+
+        dashenc_io_close(s, &c->m3u8_out, temp_filename_hls);
 
-        avio_close(out_hls);
         if (use_rename)
             if (avpriv_io_move(temp_filename_hls, filename_hls) < 0) {
                 av_log(os->ctx, AV_LOG_WARNING, "renaming file %s to %s failed\n\n", temp_filename_hls, filename_hls);
@@ -498,7 +537,7 @@ static int write_adaptation_set(AVFormatContext *s, AVIOContext *out, int as_ind
             avio_printf(out, "\t\t\t\t<AudioChannelConfiguration schemeIdUri=\"urn:mpeg:dash:23003:3:audio_channel_configuration:2011\" value=\"%d\" />\n",
                 s->streams[i]->codecpar->channels);
         }
-        output_segment_list(os, out, c, i, final);
+        output_segment_list(os, out, s, i, final);
         avio_printf(out, "\t\t\t</Representation>\n");
     }
     avio_printf(out, "\t\t</AdaptationSet>\n");
@@ -657,11 +696,12 @@ static int write_manifest(AVFormatContext *s, int final)
 
     snprintf(temp_filename, sizeof(temp_filename), use_rename ? "%s.tmp" : "%s", s->filename);
     set_http_options(&opts, c);
-    ret = s->io_open(s, &out, temp_filename, AVIO_FLAG_WRITE, &opts);
+    ret = dashenc_io_open(s, &c->mpd_out, temp_filename, &opts);
     if (ret < 0) {
         av_log(s, AV_LOG_ERROR, "Unable to open %s for writing\n", temp_filename);
         return ret;
     }
+    out = c->mpd_out;
     av_dict_free(&opts);
     avio_printf(out, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
     avio_printf(out, "<MPD xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
@@ -728,7 +768,7 @@ static int write_manifest(AVFormatContext *s, int final)
 
     avio_printf(out, "</MPD>\n");
     avio_flush(out);
-    ff_format_io_close(s, &out);
+    dashenc_io_close(s, &c->mpd_out, temp_filename);
 
     if (use_rename) {
         if ((ret = avpriv_io_move(temp_filename, s->filename)) < 0)
@@ -1115,7 +1155,7 @@ static int dash_flush(AVFormatContext *s, int final, int stream)
             snprintf(full_path, sizeof(full_path), "%s%s", c->dirname, filename);
             snprintf(temp_path, sizeof(temp_path), use_rename ? "%s.tmp" : "%s", full_path);
             set_http_options(&opts, c);
-            ret = s->io_open(s, &os->out, temp_path, AVIO_FLAG_WRITE, &opts);
+            ret = dashenc_io_open(s, &os->out, temp_path, &opts);
             if (ret < 0)
                 break;
             av_dict_free(&opts);
@@ -1133,7 +1173,7 @@ static int dash_flush(AVFormatContext *s, int final, int stream)
         if (c->single_file) {
             find_index_range(s, full_path, os->pos, &index_length);
         } else {
-            ff_format_io_close(s, &os->out);
+            dashenc_io_close(s, &os->out, temp_path);
 
             if (use_rename) {
                 ret = avpriv_io_move(temp_path, full_path);
@@ -1330,6 +1370,7 @@ static const AVOption options[] = {
     { "media_seg_name", "DASH-templated name to used for the media segments", OFFSET(media_seg_name), AV_OPT_TYPE_STRING, {.str = "chunk-stream$RepresentationID$-$Number%05d$.m4s"}, 0, 0, E },
     { "utc_timing_url", "URL of the page that will return the UTC timestamp in ISO format", OFFSET(utc_timing_url), AV_OPT_TYPE_STRING, { 0 }, 0, 0, E },
     { "http_user_agent", "override User-Agent field in HTTP header", OFFSET(user_agent), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E},
+    { "http_persistent", "Use persistent HTTP connections", OFFSET(http_persistent), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },
     { "hls_playlist", "Generate HLS playlist files(master.m3u8, media_%d.m3u8)", OFFSET(hls_playlist), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, E },
     { NULL },
 };