[vlc-devel] [PATCH] Let the threshold for discarding late displays be specified, on the command line

David R. Robison david.robison at openroadsconsulting.com
Wed Apr 8 17:10:33 CEST 2015


Any comment on this proposed patch? David

----------------------------------------------------------------------------

David R Robison

*Principal Systems Engineer*

+1 757 546 3401 (o)

+1 757 286 0022 (m)

david.robison at openroadsconsulting.com 
<mailto:david.robison at openroadsconsulting.com>

www.openroadsconsulting.com

----------------------------------------------------------------------------

Open Roads Consulting

A Q-Free Company

103 Watson Rd. Chesapeake VA 23320

On 3/30/2015 10:58 AM, David R. Robison wrote:
> Good point. Here is the revised patch.
>
> diff --git a/src/libvlc-module.c b/src/libvlc-module.c
> index 46180f5..7293a6d 100644
> --- a/src/libvlc-module.c
> +++ b/src/libvlc-module.c
> @@ -482,6 +482,10 @@ static const char *const ppsz_pos_descriptions[] =
>  #define MOUSE_EVENTS_LONGTEXT N_( \
>      "This enables handling of mouse clicks on the video." )
>
> +#define DISPLAY_LATE_THRESHOLD_TEXT N_("Display late threshold")
> +#define DISPLAY_LATE_THRESHOLD_LONGTEXT N_( \
> +    "VOUT Display late threshold in ms." )
> +
>  /*****************************************************************************
>   * Input
> ****************************************************************************/
> @@ -1605,6 +1609,9 @@ vlc_module_begin ()
>      add_module_list( "video-splitter", "video splitter", NULL,
>                       VIDEO_SPLITTER_TEXT, VIDEO_SPLITTER_LONGTEXT, 
> false )
>      add_obsolete_string( "vout-filter" ) /* since 2.0.0 */
> +
> +    add_integer( "display-late-threshold", 20, 
> DISPLAY_LATE_THRESHOLD_TEXT,
> +              DISPLAY_LATE_THRESHOLD_LONGTEXT, true )
>  #if 0
>      add_string( "pixel-ratio", "1", PIXEL_RATIO_TEXT, PIXEL_RATIO_TEXT )
>  #endif
> diff --git a/src/video_output/video_output.c 
> b/src/video_output/video_output.c
> index 40701b7..c82ebb3 100644
> --- a/src/video_output/video_output.c
> +++ b/src/video_output/video_output.c
> @@ -63,11 +63,6 @@ static void VoutDestructor(vlc_object_t *);
>   */
>  #define VOUT_REDISPLAY_DELAY (INT64_C(80000))
>
> -/**
> - * Late pictures having a delay higher than this value are thrashed.
> - */
> -#define VOUT_DISPLAY_LATE_THRESHOLD (INT64_C(20000))
> -
>  /* Better be in advance when awakening than late... */
>  #define VOUT_MWAIT_TOLERANCE (INT64_C(4000))
>
> @@ -159,6 +154,9 @@ static vout_thread_t *VoutCreate(vlc_object_t *object,
>      /* */
>      vout_InitInterlacingSupport(vout, vout->p->displayed.is_interlaced);
>
> +    vout->p->display_late_threshold = var_InheritInteger(vout, 
> "display-late-threshold") * 1000;
> +
> +
>      /* Window */
>      if (vout->p->splitter_name == NULL) {
>          vout_window_cfg_t wcfg = {
> @@ -786,7 +784,7 @@ static int 
> ThreadDisplayPreparePicture(vout_thread_t *vout, bool reuse, bool fra
>                  if (is_late_dropped && !decoded->b_force) {
>                      const mtime_t predicted = mdate() + 0; /* TODO 
> improve */
>                      const mtime_t late = predicted - decoded->date;
> -                    if (late > VOUT_DISPLAY_LATE_THRESHOLD) {
> +                    if (late > vout->p->display_late_threshold) {
>                          msg_Warn(vout, "picture is too late to be 
> displayed (missing %"PRId64" ms)", late/1000);
>                          picture_Release(decoded);
> vout_statistic_AddLost(&vout->p->statistic, 1);
> diff --git a/src/video_output/vout_internal.h 
> b/src/video_output/vout_internal.h
> index 3b01567..5b6e792 100644
> --- a/src/video_output/vout_internal.h
> +++ b/src/video_output/vout_internal.h
> @@ -112,6 +112,7 @@ struct vout_thread_sys_t
>
>      /* */
>      bool            is_late_dropped;
> +    long            display_late_threshold; /* The amount if time in 
> us that a picture can be late and still displayed */
>
>      /* Video filter2 chain */
>      struct {
>
>
> ----------------------------------------------------------------------------
>
> David R Robison
>
> *Principal Systems Engineer*
>
> +1 757 546 3401 (o)
>
> +1 757 286 0022 (m)
>
> david.robison at openroadsconsulting.com 
> <mailto:david.robison at openroadsconsulting.com>
>
> www.openroadsconsulting.com
>
> ----------------------------------------------------------------------------
>
> Open Roads Consulting
>
> A Q-Free Company
>
> 103 Watson Rd. Chesapeake VA 23320
>
> On 3/27/2015 2:27 PM, Rémi Denis-Courmont wrote:
>> Le jeudi 26 mars 2015, 14:22:16 David R. Robison a écrit :
>>> Sorry, I muffed the git send-mail. This is what I intended to send...
>>>
>>> When playing live video, sometimes the arriving packets exceed the 20ms
>>> limit for displaying late pictures. I'm proposing a change to allow this
>>> value to be set on the command line.
>>>
>>>
>>>
>>>   From 9ce5a84754b992b8a61b93f79c63baec6c4867eb Mon Sep 17 00:00:00 2001
>>> From: David R Robison<david.robison at openroadsconsulting.com>
>>> Date: Thu, 26 Mar 2015 11:13:33 -0700
>>> Subject: [PATCH] Let the threshold for discarding late displays be specified
>>> on the command line
>>>
>>> ---
>>>    src/libvlc-module.c             | 7 +++++++
>>>    src/video_output/video_output.c | 8 ++------
>>>    2 files changed, 9 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/src/libvlc-module.c b/src/libvlc-module.c
>>> index 46180f5..7293a6d 100644
>>> --- a/src/libvlc-module.c
>>> +++ b/src/libvlc-module.c
>>> @@ -482,6 +482,10 @@ static const char *const ppsz_pos_descriptions[] =
>>>    #define MOUSE_EVENTS_LONGTEXT N_( \
>>>        "This enables handling of mouse clicks on the video." )
>>>
>>> +#define DISPLAY_LATE_THRESHOLD_TEXT N_("Display late threshold")
>>> +#define DISPLAY_LATE_THRESHOLD_LONGTEXT N_( \
>>> +    "VOUT Display late threshold in ms." )
>>> +
>>>   
>>> /**************************************************************************
>>> *** * Input
>>> ****************************************************************************
>>> / @@ -1605,6 +1609,9 @@ vlc_module_begin ()
>>>        add_module_list( "video-splitter", "video splitter", NULL,
>>>                         VIDEO_SPLITTER_TEXT, VIDEO_SPLITTER_LONGTEXT, false )
>>> add_obsolete_string( "vout-filter" ) /* since 2.0.0 */
>>> +
>>> +    add_integer( "display-late-threshold", 20, DISPLAY_LATE_THRESHOLD_TEXT,
>>> +              DISPLAY_LATE_THRESHOLD_LONGTEXT, true )
>>>    #if 0
>>>        add_string( "pixel-ratio", "1", PIXEL_RATIO_TEXT, PIXEL_RATIO_TEXT )
>>>    #endif
>>> diff --git a/src/video_output/video_output.c
>>> b/src/video_output/video_output.c
>>> index 40701b7..3374154 100644
>>> --- a/src/video_output/video_output.c
>>> +++ b/src/video_output/video_output.c
>>> @@ -63,11 +63,6 @@ static void VoutDestructor(vlc_object_t *);
>>>     */
>>>    #define VOUT_REDISPLAY_DELAY (INT64_C(80000))
>>>
>>> -/**
>>> - * Late pictures having a delay higher than this value are thrashed.
>>> - */
>>> -#define VOUT_DISPLAY_LATE_THRESHOLD (INT64_C(20000))
>>> -
>>>    /* Better be in advance when awakening than late... */
>>>    #define VOUT_MWAIT_TOLERANCE (INT64_C(4000))
>>>
>>> @@ -786,7 +781,8 @@ static int ThreadDisplayPreparePicture(vout_thread_t
>>> *vout, bool reuse, bool fra
>>>                    if (is_late_dropped && !decoded->b_force) {
>>>                        const mtime_t predicted = mdate() + 0; /* TODO
>>> improve */
>>>                        const mtime_t late = predicted - decoded->date;
>>> -                    if (late > VOUT_DISPLAY_LATE_THRESHOLD) {
>>> +                    long display_late = var_InheritInteger(vout,
>>> "display-late-threshold") * 1000;
>> Contending for the vout variable lock in a time critical code path is probably
>> not a good idea.
>>
>>> +                    if (late > display_late) {
>>>                            msg_Warn(vout, "picture is too late to be
>>> displayed (missing %"PRId64" ms)", late/1000);
>>>                            picture_Release(decoded);
>>> vout_statistic_AddLost(&vout->p->statistic, 1);
>>>
>>>> When playing live video, sometimes the arriving packets exceed the 20ms
>>>> limit for displaying late pictures. I'm proposing a change to allow this
>>>> value to be set on the command line.
>>>>
>>>>
>>>>
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>
>
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