[vlc-devel] [PATCH] VLC unable to play HLS live stream

[Ilkka Ollakka]

On Thu, Aug 15, 2013 at 10:13:29AM -0400, Avishay Spitzer wrote:
> Ilkka,

Hi,

> Are you suggesting adding a new condition variable on which read will wait
> until download thread signals?

Yes, I think it would be better aproach as it avoids polling. Ofcourse
it needs timeout value so it won't get stuck.


> > Hi,

> > I think it would be better to implement this with signal wait with
> > timeout instead of polling. So download thread would signal that new
> > stuff is ready.

> > On Thu, Aug 15, 2013 at 06:52:09AM -0400, Avishay Spitzer wrote:
> > > From 768e199c6ac6d539f1a00606a26a905a5f1b1886 Mon Sep 17 00:00:00 2001
> > > From: Avishay Spitzer <savishay at gmail.com>
> > > Date: Thu, 15 Aug 2013 06:41:35 -0400
> > > Subject: [PATCH 2/2] Added a retry mechanism with backoff to the read
> > >  function of HLS module to handle situations where
> > >  stream packets may delay due to slow connections or
> > >  short playlists. In case hls_Read returns 0, the read
> > >  function will wait until new data arrives.

> > > ---
> > >  modules/stream_filter/httplive.c |   48
> > +++++++++++++++++++++++++++++++++-----
> > >  1 file changed, 42 insertions(+), 6 deletions(-)

> > > diff --git a/modules/stream_filter/httplive.c
> > b/modules/stream_filter/httplive.c
> > > index ed708bf..62ab17b 100644
> > > --- a/modules/stream_filter/httplive.c
> > > +++ b/modules/stream_filter/httplive.c
> > > @@ -2280,16 +2280,52 @@ static int Read(stream_t *s, void *buffer,
> > unsigned int i_read)
> > >  {
> > >      stream_sys_t *p_sys = s->p_sys;
> > >      ssize_t length = 0;
> > > +    uint32_t retries_counter = 0, aggregate_delay = 0;

> > >      assert(p_sys->hls_stream);

> > > -    if (p_sys->b_error)
> > > -        return 0;
> > > +    while (length == 0)
> > > +    {
> > > +     // In case an error occurred or the stream was closed return 0
> > > +        if (p_sys->b_error || !vlc_object_alive(s))
> > > +            return 0;

> > > -    /* NOTE: buffer might be NULL if caller wants to skip data */
> > > -    length = hls_Read(s, (uint8_t*) buffer, i_read);
> > > -    if (length < 0)
> > > -        return 0;
> > > +             /* NOTE: buffer might be NULL if caller wants to skip data
> > */
> > > +             length = hls_Read(s, (uint8_t*) buffer, i_read);
> > > +
> > > +             // An error has occurred in hls_Read
> > > +             if (length < 0)
> > > +                     return 0;
> > > +
> > > +             // No data is available yet so we need to wait until new
> > data will arrive.
> > > +             // We use a retry mechanism with increasing backoff (up to
> > 100ms per single sleep)
> > > +             if (length == 0)
> > > +             {
> > > +             uint32_t delay = 0;
> > > +
> > > +                     retries_counter++;
> > > +
> > > +                     if (retries_counter < 10)
> > > +                             delay = 10; // ms
> > > +                     else if (retries_counter < 25)
> > > +                             delay = 25; // ms
> > > +                     else if (retries_counter < 100)
> > > +                             delay = 50; // ms
> > > +                     else
> > > +                             delay = 100; // ms
> > > +
> > > +                     aggregate_delay += delay;
> > > +
> > > +                     msleep(delay * 1000);
> > > +             }
> > > +    }
> > > +
> > > +    if (retries_counter > 0)
> > > +    {
> > > +             msg_Info(s, "got data after %u retries (delay of [%u]ms)",
> > > +                             retries_counter,
> > > +                             aggregate_delay);
> > > +    }

> > >      p_sys->playback.offset += length;
> > >      return length;
> > --
> > Ilkka Ollakka
> > Is a computer language with goto's totally Wirth-less?

> > _______________________________________________
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-- 
Ilkka Ollakka
<gorgo> what do you get when someone cracks your debian machine ?
<gorgo> mashed potato...
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