[FFmpeg-devel] [PATCH v2 3/5] avformat/hls: add http_persistent option

[Anssi Hannula]

Hi!

Aman Gupta kirjoitti 2017-12-13 02:35:
> From: Aman Gupta <aman at tmm1.net>
> 
> This teaches the HLS demuxer to use the HTTP protocols
> multiple_requests=1 option, to take advantage of "Connection:
> Keep-Alive" when downloading playlists and segments from the HLS 
> server.
> 
> With the new option, you can avoid TCP connection and TLS negotiation
> overhead, which is particularly beneficial when streaming via a
> high-latency internet connection.
> 
> Similar to the http_persistent option recently implemented in hlsenc.c

Why is this implemented as an option instead of simply being always used 
by the demuxer?

> ---
>  doc/demuxers.texi |  3 +++
>  libavformat/hls.c | 68 
> +++++++++++++++++++++++++++++++++++++++++++++++++++----
>  2 files changed, 67 insertions(+), 4 deletions(-)
> 
> diff --git a/doc/demuxers.texi b/doc/demuxers.texi
> index 73dc0feec1..18ff7101ac 100644
> --- a/doc/demuxers.texi
> +++ b/doc/demuxers.texi
> @@ -316,6 +316,9 @@ segment index to start live streams at (negative
> values are from the end).
>  @item max_reload
>  Maximum number of times a insufficient list is attempted to be 
> reloaded.
>  Default value is 1000.
> +
> + at item http_persistent
> +Use persistent HTTP connections. Applicable only for HTTP streams.
>  @end table
> 
>  @section image2
> diff --git a/libavformat/hls.c b/libavformat/hls.c
> index ab6ff187a6..5c1895c180 100644
> --- a/libavformat/hls.c
> +++ b/libavformat/hls.c
> @@ -26,6 +26,7 @@
>   * http://tools.ietf.org/html/draft-pantos-http-live-streaming
>   */
> 
> +#include "libavformat/http.h"
>  #include "libavutil/avstring.h"
>  #include "libavutil/avassert.h"
>  #include "libavutil/intreadwrite.h"
> @@ -94,6 +95,7 @@ struct playlist {
>      AVIOContext pb;
>      uint8_t* read_buffer;
>      AVIOContext *input;
> +    int input_read_done;
>      AVFormatContext *parent;
>      int index;
>      AVFormatContext *ctx;
> @@ -206,6 +208,8 @@ typedef struct HLSContext {
>      int strict_std_compliance;
>      char *allowed_extensions;
>      int max_reload;
> +    int http_persistent;
> +    AVIOContext *playlist_pb;
>  } HLSContext;
> 
>  static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
> @@ -256,6 +260,7 @@ static void free_playlist_list(HLSContext *c)
>          av_freep(&pls->pb.buffer);
>          if (pls->input)
>              ff_format_io_close(c->ctx, &pls->input);
> +        pls->input_read_done = 0;
>          if (pls->ctx) {
>              pls->ctx->pb = NULL;
>              avformat_close_input(&pls->ctx);
> @@ -640,7 +645,24 @@ static int open_url(AVFormatContext *s,
> AVIOContext **pb, const char *url,
>      else if (strcmp(proto_name, "file") || !strncmp(url, "file,", 5))
>          return AVERROR_INVALIDDATA;
> 
> -    ret = s->io_open(s, pb, url, AVIO_FLAG_READ, &tmp);
> +    if (c->http_persistent && *pb && av_strstart(proto_name, "http", 
> NULL)) {
> +        URLContext *uc = ffio_geturlcontext(*pb);
> +        av_assert0(uc);
> +        (*pb)->eof_reached = 0;
> +        ret = ff_http_do_new_request(uc, url);
> +        if (ret == AVERROR_EXIT) {
> +            ff_format_io_close(c->ctx, &c->playlist_pb);
> +            return ret;
> +        } else if (ret < 0) {
> +            av_log(s, AV_LOG_WARNING,
> +                "keepalive request failed for '%s', retrying with new
> connection: %s\n",
> +                url, av_err2str(ret));
> +            ff_format_io_close(c->ctx, pb);
> +            ret = s->io_open(s, pb, url, AVIO_FLAG_READ, &tmp);
> +        }
> +    } else {
> +        ret = s->io_open(s, pb, url, AVIO_FLAG_READ, &tmp);
> +    }
>      if (ret >= 0) {
>          // update cookies on http response with setcookies.
>          char *new_cookies = NULL;
> @@ -683,10 +705,27 @@ static int parse_playlist(HLSContext *c, const 
> char *url,
>      char tmp_str[MAX_URL_SIZE];
>      struct segment *cur_init_section = NULL;
> 
> +    if (!in && c->http_persistent && c->playlist_pb) {
> +        in = c->playlist_pb;
> +        URLContext *uc = ffio_geturlcontext(in);
> +        av_assert0(uc);
> +        in->eof_reached = 0;
> +        ret = ff_http_do_new_request(uc, url);
> +        if (ret == AVERROR_EXIT) {
> +            ff_format_io_close(c->ctx, &c->playlist_pb);
> +            return ret;
> +        } else if (ret < 0) {
> +            av_log(c->ctx, AV_LOG_WARNING,
> +                "keepalive request failed for '%s', retrying with new
> connection: %s\n",
> +                url, av_err2str(ret));
> +            ff_format_io_close(c->ctx, &c->playlist_pb);
> +            in = NULL;
> +        }
> +    }
> +

The above code seems duplicated, please put it in a common function.


[..]
-- 
Anssi Hannula