[FFmpeg-devel] [PATCH 1/3] ffplay: calculate target clock dynamically, make code more readable
Marton Balint
cus at passwd.hu
Mon Oct 10 20:59:08 CEST 2011
Since target clock is based on the current A-V delay, it is better calculate it
when we actually need it rather than when we put a picture in the picture
queue.
The patch also makes a code a bit more readable by renaming some delay
variables to duration, and converting compute_target_time to a delay
calculating function which does not modify the state. Factoring out the
iteration of the pictq to standalone function is also done in this patch.
Signed-off-by: Marton Balint <cus at passwd.hu>
---
ffplay.c | 97 ++++++++++++++++++++++++++++++++------------------------------
1 files changed, 50 insertions(+), 47 deletions(-)
diff --git a/ffplay.c b/ffplay.c
index f56c2d7..65b0a2d 100644
--- a/ffplay.c
+++ b/ffplay.c
@@ -98,9 +98,9 @@ typedef struct PacketQueue {
typedef struct VideoPicture {
double pts; ///<presentation time stamp for this picture
- double target_clock; ///<av_gettime() time at which this should be displayed ideally
double duration; ///<expected duration of the frame
int64_t pos; ///<byte position in file
+ int skip;
SDL_Overlay *bmp;
int width, height; /* source height & width */
int allocated;
@@ -197,7 +197,7 @@ typedef struct VideoState {
double frame_timer;
double frame_last_pts;
- double frame_last_delay;
+ double frame_last_duration;
double video_clock; ///<pts of last decoded frame / predicted pts of next decoded frame
int video_stream;
AVStream *video_st;
@@ -1071,19 +1071,9 @@ static void stream_toggle_pause(VideoState *is)
is->paused = !is->paused;
}
-static double compute_target_time(double frame_current_pts, VideoState *is)
+static double compute_target_delay(double delay, VideoState *is)
{
- double delay, sync_threshold, diff;
-
- /* compute nominal delay */
- delay = frame_current_pts - is->frame_last_pts;
- if (delay <= 0 || delay >= 10.0) {
- /* if incorrect delay, use previous one */
- delay = is->frame_last_delay;
- } else {
- is->frame_last_delay = delay;
- }
- is->frame_last_pts = frame_current_pts;
+ double sync_threshold, diff;
/* update delay to follow master synchronisation source */
if (((is->av_sync_type == AV_SYNC_AUDIO_MASTER && is->audio_st) ||
@@ -1103,12 +1093,22 @@ static double compute_target_time(double frame_current_pts, VideoState *is)
delay = 2 * delay;
}
}
- is->frame_timer += delay;
- av_dlog(NULL, "video: delay=%0.3f pts=%0.3f A-V=%f\n",
- delay, frame_current_pts, -diff);
+ av_dlog(NULL, "video: delay=%0.3f A-V=%f\n",
+ delay, -diff);
- return is->frame_timer;
+ return delay;
+}
+
+static void pictq_next_picture(VideoState *is) {
+ /* update queue size and signal for next picture */
+ if (++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE)
+ is->pictq_rindex = 0;
+
+ SDL_LockMutex(is->pictq_mutex);
+ is->pictq_size--;
+ SDL_CondSignal(is->pictq_cond);
+ SDL_UnlockMutex(is->pictq_mutex);
}
/* called to display each frame */
@@ -1125,34 +1125,45 @@ retry:
//nothing to do, no picture to display in the que
} else {
double time= av_gettime()/1000000.0;
- double next_target;
+ double last_duration, duration, delay;
/* dequeue the picture */
vp = &is->pictq[is->pictq_rindex];
- if(time < vp->target_clock)
+ if (vp->skip) {
+ pictq_next_picture(is);
+ goto retry;
+ }
+
+ /* compute nominal last_duration */
+ last_duration = vp->pts - is->frame_last_pts;
+ if (last_duration > 0 && last_duration < 10.0) {
+ /* if duration of the last frame was sane, update last_duration in video state */
+ is->frame_last_duration = last_duration;
+ }
+ delay = compute_target_delay(is->frame_last_duration, is);
+
+ if(time < is->frame_timer + delay)
return;
+
+ is->frame_last_pts = vp->pts;
+ is->frame_timer += delay;
+
/* update current video pts */
is->video_current_pts = vp->pts;
is->video_current_pts_drift = is->video_current_pts - time;
is->video_current_pos = vp->pos;
- if(is->pictq_size > 1){
- VideoPicture *nextvp= &is->pictq[(is->pictq_rindex+1)%VIDEO_PICTURE_QUEUE_SIZE];
- assert(nextvp->target_clock >= vp->target_clock);
- next_target= nextvp->target_clock;
- }else{
- next_target= vp->target_clock + vp->duration;
+
+ if(is->pictq_size > 1) {
+ VideoPicture *nextvp= &is->pictq[(is->pictq_rindex+1)%VIDEO_PICTURE_QUEUE_SIZE];
+ duration = nextvp->pts - vp->pts; // More accurate this way, 1/time_base is often not reflecting FPS
+ } else {
+ duration = vp->duration;
}
- if((framedrop>0 || (framedrop && is->audio_st)) && time > next_target){
+
+ if((framedrop>0 || (framedrop && is->audio_st)) && time > is->frame_timer + duration){
is->skip_frames *= 1.0 + FRAME_SKIP_FACTOR;
if(is->pictq_size > 1){
- /* update queue size and signal for next picture */
- if (++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE)
- is->pictq_rindex = 0;
-
- SDL_LockMutex(is->pictq_mutex);
- is->pictq_size--;
- SDL_CondSignal(is->pictq_cond);
- SDL_UnlockMutex(is->pictq_mutex);
+ pictq_next_picture(is);
goto retry;
}
}
@@ -1205,14 +1216,7 @@ retry:
if (!display_disable)
video_display(is);
- /* update queue size and signal for next picture */
- if (++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE)
- is->pictq_rindex = 0;
-
- SDL_LockMutex(is->pictq_mutex);
- is->pictq_size--;
- SDL_CondSignal(is->pictq_cond);
- SDL_UnlockMutex(is->pictq_mutex);
+ pictq_next_picture(is);
}
} else if (is->audio_st) {
/* draw the next audio frame */
@@ -1425,13 +1429,12 @@ static int queue_picture(VideoState *is, AVFrame *src_frame, double pts1, int64_
vp->pts = pts;
vp->pos = pos;
+ vp->skip = 0;
/* now we can update the picture count */
if (++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE)
is->pictq_windex = 0;
SDL_LockMutex(is->pictq_mutex);
- vp->target_clock= compute_target_time(vp->pts, is);
-
is->pictq_size++;
SDL_UnlockMutex(is->pictq_mutex);
}
@@ -1451,7 +1454,7 @@ static int get_video_frame(VideoState *is, AVFrame *frame, int64_t *pts, AVPacke
SDL_LockMutex(is->pictq_mutex);
//Make sure there are no long delay timers (ideally we should just flush the que but thats harder)
for (i = 0; i < VIDEO_PICTURE_QUEUE_SIZE; i++) {
- is->pictq[i].target_clock= 0;
+ is->pictq[i].skip = 1;
}
while (is->pictq_size && !is->videoq.abort_request) {
SDL_CondWait(is->pictq_cond, is->pictq_mutex);
@@ -1460,7 +1463,7 @@ static int get_video_frame(VideoState *is, AVFrame *frame, int64_t *pts, AVPacke
SDL_UnlockMutex(is->pictq_mutex);
is->frame_last_pts = AV_NOPTS_VALUE;
- is->frame_last_delay = 0;
+ is->frame_last_duration = 0;
is->frame_timer = (double)av_gettime() / 1000000.0;
is->skip_frames = 1;
is->skip_frames_index = 0;
--
1.7.3.4
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