[FFmpeg-devel,2/2] avformat/dashenc: Persistent HTTP connections supported as an option

From: Karthick Jeyapal <kjeyapal@akamai.com>

---
 libavformat/dashenc.c | 67 +++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 54 insertions(+), 13 deletions(-)

On 12/15/17 9:36 PM, Karthick J wrote:
> From: Karthick Jeyapal <kjeyapal@akamai.com>
>
> ---
>   libavformat/dashenc.c | 67 +++++++++++++++++++++++++++++++++++++++++----------
>   1 file changed, 54 insertions(+), 13 deletions(-)
>
> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
> index 5687530..e7d1a0d 100644
> --- a/libavformat/dashenc.c
> +++ b/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 = hls_get_int_from_double(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)
> @@ -1094,7 +1134,7 @@ 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);
> @@ -1112,7 +1152,7 @@ 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);
> @@ -1309,6 +1349,7 @@ 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 },
Forgot to update the muxers.texi about the new option.
I will send a new patchset v2 with that update. Sorry for any 
inconvenience caused.
>       { "hls_playlist", "Generate HLS playlist files(master.m3u8, media_%d.m3u8)", OFFSET(hls_playlist), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, E },
>       { NULL },
>   };