[vlc-devel] [PATCH] Inproved buffering accuracy and no rebuffering on ignored

[David R Robison]

Any thoughts on this? David

David R Robison
Open Roads Consulting, Inc.
103 Watson Road, Chesapeake, VA 23320
phone: (757) 546-3401
e-mail: drrobison at openroadsconsulting.com
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On 10/1/2013 10:40 AM, David Robison wrote:
> To test this change, I used a MiniMaxwell which allows me to introduce jitter, delay, and packet re-ordering in the video stream. I ran for over 12 hours with no effect on the video and no increase in buffer size. I'm reattaching the final patch here. I've made 2 basic changes to the buffering strategy:
>
> 1) I now check to see if I and done buffering on both the ES_OUT_SET_PCR and ES_OUT_SET_GROUP_PCR calls. This causes the buffered amount to be checked more frequently and prevents over buffering which I have seen in some instances
> 2) When ignoring the jitter, I do not flush the buffer and rebuffer, since I am not increasing the buffer size anyway. Instead I just reset the PCR and continue on.
>
> Here is the final patch, Any comments?
> David
>
> diff --git a/src/input/es_out.c b/src/input/es_out.c
> index 68acf5e..c2431ba 100644
> --- a/src/input/es_out.c
> +++ b/src/input/es_out.c
> @@ -2309,14 +2309,14 @@ static int EsOutControlLocked( es_out_t *out, int i_query, va_list args )
>                               EsOutIsExtraBufferingAllowed( out ),
>                               i_pcr, mdate() );
>   
> -        if( p_pgrm == p_sys->p_pgrm )
> +        if( p_sys->b_buffering )
>           {
> -            if( p_sys->b_buffering )
> -            {
> -                /* Check buffering state on master clock update */
> -                EsOutDecodersStopBuffering( out, false );
> -            }
> -            else if( b_late && ( !p_sys->p_input->p->p_sout ||
> +            /* Check buffering state on master clock update */
> +            EsOutDecodersStopBuffering( out, false );
> +        }
> +        else if( p_pgrm == p_sys->p_pgrm )
> +        {
> +            if( b_late && ( !p_sys->p_input->p->p_sout ||
>                                    !p_sys->p_input->p->b_out_pace_control ) )
>               {
>                   const mtime_t i_pts_delay_base = p_sys->i_pts_delay - p_sys->i_pts_jitter;
> @@ -2330,19 +2330,23 @@ static int EsOutControlLocked( es_out_t *out, int i_query, va_list args )
>                                "ES_OUT_SET_(GROUP_)PCR  is called too late (jitter of %d ms ignored)",
>                                (int)(i_pts_delay - i_pts_delay_base) / 1000 );
>                       i_pts_delay = p_sys->i_pts_delay;
> +
> +                    /* reset clock */
> +                    for( int i = 0; i < p_sys->i_pgrm; i++ )
> +                      input_clock_Reset( p_sys->pgrm[i]->p_clock );
>                   }
>                   else
>                   {
>                       msg_Err( p_sys->p_input,
>                                "ES_OUT_SET_(GROUP_)PCR  is called too late (pts_delay increased to %d ms)",
>                                (int)(i_pts_delay/1000) );
> -                }
>   
> -                /* Force a rebufferization when we are too late */
> +                    /* Force a rebufferization when we are too late */
>   
> -                /* It is not really good, as we throw away already buffered data
> -                 * TODO have a mean to correctly reenter bufferization */
> -                es_out_Control( out, ES_OUT_RESET_PCR );
> +                    /* It is not really good, as we throw away already buffered data
> +                     * TODO have a mean to correctly reenter bufferization */
> +                    es_out_Control( out, ES_OUT_RESET_PCR );
> +                }
>   
>                   es_out_SetJitter( out, i_pts_delay_base, i_pts_delay - i_pts_delay_base, p_sys->i_cr_average );
>               }
> -- 
> 1.7.9.5
>
>    _____
> From: Rémi Denis-Courmont [mailto:remi at remlab.net]
> To: Mailing list for VLC media player developers [mailto:vlc-devel at videolan.org]
> Sent: Thu, 26 Sep 2013 10:03:03 -0400
> Subject: Re: [vlc-devel] [PATCH] Do not rebuffer if not increasing buffer	size
>
> Is there any easy way to test it?
>



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