[FFmpeg-devel] [FFmpeg-cvslog] avformat/hls: add http_persistent option

[wm4]

On Tue, 26 Dec 2017 02:14:11 +0000
Aman Gupta <ffmpeg at tmm1.net> wrote:

> On Mon, Dec 25, 2017 at 1:03 PM Michael Niedermayer <michael at niedermayer.cc>
> wrote:
> 
> > On Mon, Dec 25, 2017 at 06:08:11PM +0000, Aman Gupta wrote:  
> > > On Mon, Dec 25, 2017 at 9:58 AM Michael Niedermayer  
> > <michael at niedermayer.cc>  
> > > wrote:
> > >  
> > > > On Fri, Dec 22, 2017 at 11:00:34PM +0000, Aman Gupta wrote:  
> > > > > ffmpeg | branch: master | Aman Gupta <aman at tmm1.net> | Wed Oct  4  
> > > > 14:52:52 2017 -0700| [b7d6c0cd48dac7869b9e6803e2d47d05a4fa373b] |
> > > > committer: Aman Gupta  
> > > > >
> > > > > avformat/hls: add http_persistent option
> > > > >
> > > > > 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  
> > > > >
> > > > > Signed-off-by: Aman Gupta <aman at tmm1.net>
> > > > > Signed-off-by: Anssi Hannula <anssi.hannula at iki.fi>
> > > > >  
> > > > > >  
> > > >  
> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b7d6c0cd48dac7869b9e6803e2d47d05a4fa373b  
> > > > > ---
> > > > >
> > > > >  doc/demuxers.texi |  4 ++++
> > > > >  libavformat/hls.c | 72  
> > > > +++++++++++++++++++++++++++++++++++++++++++++++++++----  
> > > > >  2 files changed, 72 insertions(+), 4 deletions(-)  
> > > >
> > > > This causes ffmpeg to infinite loop with simplehttpd.py  
> > >
> > >
> > > Is that the same as SimpleHTTPServer.py?
> > >
> > > Sounds like it doesn't support persistent connections, but also isn't
> > > returning "Connection: close" in the response.
> > >
> > > I can investigate if you tell me where to find that httpd server.  
> >
> > Iam not sure where i got it from or its original source but it matches the
> > source here:
> >
> >
> > https://www.linuxjournal.com/content/tech-tip-really-simple-http-server-python  
> 
> 
> Thanks.
> 
> I was able to reproduce the issue. It appears to be because the simple http
> server is quite too simple, and can only handle one request at a time. The
> http_multiple option tries to make a second request before the first is
> completed, causing a deadlock.
> 
> I guess we could disable http_multiple by default...
> 
> Aman
> 
> <https://www.linuxjournal.com/content/tech-tip-really-simple-http-server-python>

So I hear this causes some infinite loop. Could this be made adaptive?

What does the HTTP spec say about this, and what do other HTTP
implementations do here?