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mpv/video/out/present_sync.h

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vo: move wayland presentation to separate files Wayland had some specific code that it used for implementing the presentation time protocol. It turns out that xorg's present extension is extremely similar, so it would be silly to duplicate this whole mess again. Factor this out to separate, independent code and introduce the mp_present struct which is used for handling the ust/msc values and some other associated values. Also, add in some helper functions so all the dirty details live specifically in present_sync. The only wayland-specific part is actually obtaining ust/msc values. Since only wayland or xorg are expected to use this, add a conditional to the build that only adds this file when either one of those are present. You may observe that sbc is completely omitted. This field existed in wayland, but was completely unused (presentation time doesn't return this). Xorg's present extension also doesn't use this so just get rid of it all together. The actual calculation is slightly altered so it is correct for our purposes. We want to get the presentation event of the last frame that was just occured (this function executes right after the buffer swap). The adjustment is to just remove the vsync_duration subtraction. Also, The overly-complicated queue approach is removed. This has no actual use in practice (on wayland or xorg). Presentation statistics are only ever used after the immediate preceding swap to update vsync timings or thrown away.
2022-06-10 16:49:28 +00:00
/*
* This file is part of mpv video player.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef MP_PRESENT_SYNC_H
#define MP_PRESENT_SYNC_H
#include <stdbool.h>
#include <stdint.h>
#include "vo.h"
/* Generic helpers for obtaining presentation feedback from
* backend APIs. This requires ust/msc values. */
present_sync: rewrite around linked list When this was originally written, the queuing/list approach was deliberately removed since it adds more complication and xorg/wayland don't really use it anyway. In practice, you only really have one frame in flight with presentation timestamps. However, one slight annoyance is that the drm code has its own thing which is almost exactly the same and does its own calculations. Ideally, we'd port drm to this instead, but the implementation there takes into account N-frames in flight which probably does actually work. So we need to make present_sync smarter and be able to handle this. mpv does actually have its own linked list implementation already which is a good fit for this. mp_present becomes the list and each mp_present_entry has its own set of timestamps. During initialization, we create all the entries we need and then simply treat it like a queue during the lifecycle of the VO. When an entry is fully used (present_sync_get_info), then we remove it from the list, zero it out, and append it to the end for future use. This avoids needing to allocate memory on every frame (which is what drm currently does) and allows for a reasonable number of in flight frames at the same time as this should never grow to some obscene number. The nice thing is that current users of present_sync don't need to change anything besides the initialization step.
2023-11-02 18:41:32 +00:00
struct mp_present_entry {
int64_t ust;
int64_t msc;
vo: move wayland presentation to separate files Wayland had some specific code that it used for implementing the presentation time protocol. It turns out that xorg's present extension is extremely similar, so it would be silly to duplicate this whole mess again. Factor this out to separate, independent code and introduce the mp_present struct which is used for handling the ust/msc values and some other associated values. Also, add in some helper functions so all the dirty details live specifically in present_sync. The only wayland-specific part is actually obtaining ust/msc values. Since only wayland or xorg are expected to use this, add a conditional to the build that only adds this file when either one of those are present. You may observe that sbc is completely omitted. This field existed in wayland, but was completely unused (presentation time doesn't return this). Xorg's present extension also doesn't use this so just get rid of it all together. The actual calculation is slightly altered so it is correct for our purposes. We want to get the presentation event of the last frame that was just occured (this function executes right after the buffer swap). The adjustment is to just remove the vsync_duration subtraction. Also, The overly-complicated queue approach is removed. This has no actual use in practice (on wayland or xorg). Presentation statistics are only ever used after the immediate preceding swap to update vsync timings or thrown away.
2022-06-10 16:49:28 +00:00
int64_t vsync_duration;
present_sync: rewrite around linked list When this was originally written, the queuing/list approach was deliberately removed since it adds more complication and xorg/wayland don't really use it anyway. In practice, you only really have one frame in flight with presentation timestamps. However, one slight annoyance is that the drm code has its own thing which is almost exactly the same and does its own calculations. Ideally, we'd port drm to this instead, but the implementation there takes into account N-frames in flight which probably does actually work. So we need to make present_sync smarter and be able to handle this. mpv does actually have its own linked list implementation already which is a good fit for this. mp_present becomes the list and each mp_present_entry has its own set of timestamps. During initialization, we create all the entries we need and then simply treat it like a queue during the lifecycle of the VO. When an entry is fully used (present_sync_get_info), then we remove it from the list, zero it out, and append it to the end for future use. This avoids needing to allocate memory on every frame (which is what drm currently does) and allows for a reasonable number of in flight frames at the same time as this should never grow to some obscene number. The nice thing is that current users of present_sync don't need to change anything besides the initialization step.
2023-11-02 18:41:32 +00:00
int64_t skipped_vsyncs;
int64_t queue_display_time;
struct {
struct mp_present_entry *next, *prev;
} list_node;
};
struct mp_present {
struct mp_present_entry *head, *tail;
present_sync: only save as many entries as the swapchain depth Saving more than the swapchain depth is just wasteful. We can just save a copy of the vo_opts here and check the value whenever we're updating values.
2023-11-06 22:35:04 +00:00
struct mp_vo_opts *opts;
vo: move wayland presentation to separate files Wayland had some specific code that it used for implementing the presentation time protocol. It turns out that xorg's present extension is extremely similar, so it would be silly to duplicate this whole mess again. Factor this out to separate, independent code and introduce the mp_present struct which is used for handling the ust/msc values and some other associated values. Also, add in some helper functions so all the dirty details live specifically in present_sync. The only wayland-specific part is actually obtaining ust/msc values. Since only wayland or xorg are expected to use this, add a conditional to the build that only adds this file when either one of those are present. You may observe that sbc is completely omitted. This field existed in wayland, but was completely unused (presentation time doesn't return this). Xorg's present extension also doesn't use this so just get rid of it all together. The actual calculation is slightly altered so it is correct for our purposes. We want to get the presentation event of the last frame that was just occured (this function executes right after the buffer swap). The adjustment is to just remove the vsync_duration subtraction. Also, The overly-complicated queue approach is removed. This has no actual use in practice (on wayland or xorg). Presentation statistics are only ever used after the immediate preceding swap to update vsync timings or thrown away.
2022-06-10 16:49:28 +00:00
};
present_sync: only save as many entries as the swapchain depth Saving more than the swapchain depth is just wasteful. We can just save a copy of the vo_opts here and check the value whenever we're updating values.
2023-11-06 22:35:04 +00:00
struct mp_present *mp_present_initialize(void *talloc_ctx, struct mp_vo_opts *opts, int entries);
present_sync: rewrite around linked list When this was originally written, the queuing/list approach was deliberately removed since it adds more complication and xorg/wayland don't really use it anyway. In practice, you only really have one frame in flight with presentation timestamps. However, one slight annoyance is that the drm code has its own thing which is almost exactly the same and does its own calculations. Ideally, we'd port drm to this instead, but the implementation there takes into account N-frames in flight which probably does actually work. So we need to make present_sync smarter and be able to handle this. mpv does actually have its own linked list implementation already which is a good fit for this. mp_present becomes the list and each mp_present_entry has its own set of timestamps. During initialization, we create all the entries we need and then simply treat it like a queue during the lifecycle of the VO. When an entry is fully used (present_sync_get_info), then we remove it from the list, zero it out, and append it to the end for future use. This avoids needing to allocate memory on every frame (which is what drm currently does) and allows for a reasonable number of in flight frames at the same time as this should never grow to some obscene number. The nice thing is that current users of present_sync don't need to change anything besides the initialization step.
2023-11-02 18:41:32 +00:00
vo: move wayland presentation to separate files Wayland had some specific code that it used for implementing the presentation time protocol. It turns out that xorg's present extension is extremely similar, so it would be silly to duplicate this whole mess again. Factor this out to separate, independent code and introduce the mp_present struct which is used for handling the ust/msc values and some other associated values. Also, add in some helper functions so all the dirty details live specifically in present_sync. The only wayland-specific part is actually obtaining ust/msc values. Since only wayland or xorg are expected to use this, add a conditional to the build that only adds this file when either one of those are present. You may observe that sbc is completely omitted. This field existed in wayland, but was completely unused (presentation time doesn't return this). Xorg's present extension also doesn't use this so just get rid of it all together. The actual calculation is slightly altered so it is correct for our purposes. We want to get the presentation event of the last frame that was just occured (this function executes right after the buffer swap). The adjustment is to just remove the vsync_duration subtraction. Also, The overly-complicated queue approach is removed. This has no actual use in practice (on wayland or xorg). Presentation statistics are only ever used after the immediate preceding swap to update vsync timings or thrown away.
2022-06-10 16:49:28 +00:00
// Used during the get_vsync call to deliver the presentation statistics to the VO.
void present_sync_get_info(struct mp_present *present, struct vo_vsync_info *info);
// Called after every buffer swap to update presentation statistics.
void present_sync_swap(struct mp_present *present);
// Called anytime the backend delivers new ust/msc values.
present_sync: rename function to present_sync_update_values This had to have been a mistake. It was just confusing.
2023-11-02 21:03:03 +00:00
void present_sync_update_values(struct mp_present *present, int64_t ust,
vo: move wayland presentation to separate files Wayland had some specific code that it used for implementing the presentation time protocol. It turns out that xorg's present extension is extremely similar, so it would be silly to duplicate this whole mess again. Factor this out to separate, independent code and introduce the mp_present struct which is used for handling the ust/msc values and some other associated values. Also, add in some helper functions so all the dirty details live specifically in present_sync. The only wayland-specific part is actually obtaining ust/msc values. Since only wayland or xorg are expected to use this, add a conditional to the build that only adds this file when either one of those are present. You may observe that sbc is completely omitted. This field existed in wayland, but was completely unused (presentation time doesn't return this). Xorg's present extension also doesn't use this so just get rid of it all together. The actual calculation is slightly altered so it is correct for our purposes. We want to get the presentation event of the last frame that was just occured (this function executes right after the buffer swap). The adjustment is to just remove the vsync_duration subtraction. Also, The overly-complicated queue approach is removed. This has no actual use in practice (on wayland or xorg). Presentation statistics are only ever used after the immediate preceding swap to update vsync timings or thrown away.
2022-06-10 16:49:28 +00:00
int64_t msc);
#endif /* MP_PRESENT_SYNC_H */