[FFmpeg-devel] [PATCH v2 1/1] avformat/http: flushing tcp receive buffer when it is write only mode

Jeyapal, Karthick kjeyapal at akamai.com
Fri Apr 20 09:40:20 EEST 2018



´╗┐On 4/4/18, 4:38 PM, "vdixit at akamai.com" <vdixit at akamai.com> wrote:
>
>From: Vishwanath Dixit <vdixit at akamai.com>
>
>In write only mode, the TCP receive buffer's data keeps growing with
>http response messages and the buffer eventually becomes full.
>This results in zero tcp window size, which in turn causes unwanted
>issues, like, terminated tcp connection. The issue is apparent when
>http persistent connection is enabled in hls/dash live streaming use
>cases. To overcome this issue, the logic here reads the buffer data
>when a file transfer is completed, so that any accumulated data in
>the recieve buffer gets flushed out.
>---
> libavformat/http.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
>diff --git a/libavformat/http.c b/libavformat/http.c
>index 983034f..0c39e9c 100644
>--- a/libavformat/http.c
>+++ b/libavformat/http.c
>@@ -1627,6 +1627,18 @@ static int http_shutdown(URLContext *h, int flags)
>         ((flags & AVIO_FLAG_READ) && s->chunked_post && s->listen)) {
>         ret = ffurl_write(s->hd, footer, sizeof(footer) - 1);
>         ret = ret > 0 ? 0 : ret;
>+        /* flush the receive buffer when it is write only mode */
>+        if (!(flags & AVIO_FLAG_READ)) {
>+            char buf[1024];
>+            int read_ret;
>+            s->hd->flags |= AVIO_FLAG_NONBLOCK;
>+            read_ret = ffurl_read(s->hd, buf, sizeof(buf));
>+            s->hd->flags &= ~AVIO_FLAG_NONBLOCK;
>+            if (read_ret < 0 && read_ret != AVERROR(EAGAIN)) {
>+                av_log(h, AV_LOG_ERROR, "URL read error:  %d\n", read_ret);
>+                ret = read_ret;
>+            }
>+        }
>         s->end_chunked_post = 1;
>     }
Pushed.



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