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vo: move DR helper code to a separate source file 

So it can be reused by vo_libmpv.c, which needs to use it in a slightly
different way.
This commit is contained in:
wm4 2018-04-20 17:48:44 +02:00 committed by Jan Ekström
parent 65f0825315
commit 76844c9c51
5 changed files with 184 additions and 91 deletions
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130
video/out/dr_helper.c Normal file
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@ -0,0 +1,130 @@
#include <stdlib.h>
#include <assert.h>
#include <pthread.h>
#include <libavutil/buffer.h>
#include "mpv_talloc.h"
#include "misc/dispatch.h"
#include "osdep/atomic.h"
#include "video/mp_image.h"
#include "dr_helper.h"
struct dr_helper {
pthread_t thread;
struct mp_dispatch_queue *dispatch;
atomic_ullong dr_in_flight;
struct mp_image *(*get_image)(void *ctx, int imgfmt, int w, int h,
int stride_align);
void *get_image_ctx;
};
static void dr_helper_destroy(void *ptr)
{
struct dr_helper *dr = ptr;
// All references must have been freed on destruction, or we'll have
// dangling pointers.
assert(atomic_load(&dr->dr_in_flight) == 0);
}
struct dr_helper *dr_helper_create(struct mp_dispatch_queue *dispatch,
struct mp_image *(*get_image)(void *ctx, int imgfmt, int w, int h,
int stride_align),
void *get_image_ctx)
{
struct dr_helper *dr = talloc_ptrtype(NULL, dr);
talloc_set_destructor(dr, dr_helper_destroy);
*dr = (struct dr_helper){
.thread = pthread_self(),
.dispatch = dispatch,
.dr_in_flight = ATOMIC_VAR_INIT(0),
.get_image = get_image,
.get_image_ctx = get_image_ctx,
};
return dr;
}
struct free_dr_context {
struct dr_helper *dr;
AVBufferRef *ref;
};
static void dr_thread_free(void *ptr)
{
struct free_dr_context *ctx = ptr;
unsigned long long v = atomic_fetch_add(&ctx->dr->dr_in_flight, -1);
assert(v); // value before sub is 0 - unexpected underflow.
av_buffer_unref(&ctx->ref);
talloc_free(ctx);
}
static void free_dr_buffer_on_dr_thread(void *opaque, uint8_t *data)
{
struct free_dr_context *ctx = opaque;
// The image could be unreffed even on the DR thread. In practice, this
// matters most on DR destruction.
if (pthread_equal(ctx->dr->thread, pthread_self())) {
dr_thread_free(ctx);
} else {
mp_dispatch_run(ctx->dr->dispatch, dr_thread_free, ctx);
}
}
struct get_image_cmd {
struct dr_helper *dr;
int imgfmt, w, h, stride_align;
struct mp_image *res;
};
static void sync_get_image(void *ptr)
{
struct get_image_cmd *cmd = ptr;
struct dr_helper *dr = cmd->dr;
cmd->res = dr->get_image(dr->get_image_ctx, cmd->imgfmt, cmd->w, cmd->h,
cmd->stride_align);
if (!cmd->res)
return;
// We require exactly 1 AVBufferRef.
assert(cmd->res->bufs[0]);
assert(!cmd->res->bufs[1]);
// Apply some magic to get it free'd on the DR thread as well. For this to
// work, we create a dummy-ref that aliases the original ref, which is why
// the original ref must be writable in the first place. (A newly allocated
// image should be always writable of course.)
assert(mp_image_is_writeable(cmd->res));
struct free_dr_context *ctx = talloc_zero(NULL, struct free_dr_context);
*ctx = (struct free_dr_context){
.dr = dr,
.ref = cmd->res->bufs[0],
};
AVBufferRef *new_ref = av_buffer_create(ctx->ref->data, ctx->ref->size,
free_dr_buffer_on_dr_thread, ctx, 0);
if (!new_ref)
abort(); // tiny malloc OOM
cmd->res->bufs[0] = new_ref;
atomic_fetch_add(&dr->dr_in_flight, 1);
}
struct mp_image *dr_helper_get_image(struct dr_helper *dr, int imgfmt,
int w, int h, int stride_align)
{
struct get_image_cmd cmd = {
.dr = dr,
.imgfmt = imgfmt, .w = w, .h = h, .stride_align = stride_align,
};
mp_dispatch_run(dr->dispatch, sync_get_image, &cmd);
return cmd.res;
}

20
video/out/dr_helper.h Normal file
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@ -0,0 +1,20 @@
#pragma once
// This is a helper for implementing thread-safety for DR callbacks. These need
// to allocate GPU buffers on the GPU thread (e.g. OpenGL with its forced TLS),
// and the buffers also need to be freed on the GPU thread.
struct dr_helper;
struct mp_image;
struct mp_dispatch_queue;
// This MUST be called on the "target" thread (it will call pthread_self()).
// dr_helper_get_image() calls will use the dispatch queue to run get_image on
// the target thread too.
struct dr_helper *dr_helper_create(struct mp_dispatch_queue *dispatch,
struct mp_image *(*get_image)(void *ctx, int imgfmt, int w, int h,
int stride_align),
void *get_image_ctx);
struct mp_image *dr_helper_get_image(struct dr_helper *dr, int imgfmt,
int w, int h, int stride_align);

116
video/out/vo.c
View File

@ -23,8 +23,6 @@
#include <pthread.h>
#include <math.h>
#include <libavutil/buffer.h>
#include "mpv_talloc.h"
#include "config.h"
@ -37,6 +35,7 @@
#include "misc/bstr.h"
#include "vo.h"
#include "aspect.h"
#include "dr_helper.h"
#include "input/input.h"
#include "options/m_config.h"
#include "common/msg.h"
@ -111,8 +110,7 @@ const struct vo_driver *const video_out_drivers[] =
struct vo_internal {
pthread_t thread;
struct mp_dispatch_queue *dispatch;
atomic_ullong dr_in_flight;
struct dr_helper *dr_helper;
// --- The following fields are protected by lock
pthread_mutex_t lock;
@ -1004,6 +1002,13 @@ void vo_disable_external_renderloop(struct vo *vo)
in->external_renderloop_drive = false;
}
static struct mp_image *get_image_vo(void *ctx, int imgfmt, int w, int h,
int stride_align)
{
struct vo *vo = ctx;
return vo->driver->get_image(vo, imgfmt, w, h, stride_align);
}
static void *vo_thread(void *ptr)
{
struct vo *vo = ptr;
@ -1012,10 +1017,13 @@ static void *vo_thread(void *ptr)
mpthread_set_name("vo");
if (vo->driver->get_image)
in->dr_helper = dr_helper_create(in->dispatch, get_image_vo, vo);
int r = vo->driver->preinit(vo) ? -1 : 0;
mp_rendezvous(vo, r); // init barrier
if (r < 0)
return NULL;
goto done;
read_opts(vo);
update_display_fps(vo);
@ -1072,7 +1080,8 @@ static void *vo_thread(void *ptr)
talloc_free(in->current_frame);
in->current_frame = NULL;
vo->driver->uninit(vo);
assert(atomic_load(&vo->in->dr_in_flight) == 0);
done:
TA_FREEP(&in->dr_helper);
return NULL;
}
@ -1346,6 +1355,16 @@ struct vo_frame *vo_get_current_vo_frame(struct vo *vo)
return r;
}
struct mp_image *vo_get_image(struct vo *vo, int imgfmt, int w, int h,
int stride_align)
{
if (vo->driver->get_image_ts)
return vo->driver->get_image_ts(vo, imgfmt, w, h, stride_align);
if (vo->in->dr_helper)
return dr_helper_get_image(vo->in->dr_helper, imgfmt, w, h, stride_align);
return NULL;
}
static void destroy_frame(void *p)
{
struct vo_frame *frame = p;
@ -1385,88 +1404,3 @@ int lookup_keymap_table(const struct mp_keymap *map, int key)
map++;
return map->to;
}
struct free_dr_context {
struct vo *vo;
AVBufferRef *ref;
};
static void vo_thread_free(void *ptr)
{
struct free_dr_context *ctx = ptr;
unsigned long long v = atomic_fetch_add(&ctx->vo->in->dr_in_flight, -1);
assert(v); // value before sub is 0 - unexpected underflow.
av_buffer_unref(&ctx->ref);
talloc_free(ctx);
}
static void free_dr_buffer_on_vo_thread(void *opaque, uint8_t *data)
{
struct free_dr_context *ctx = opaque;
// The image could be unreffed even on the VO thread. In practice, this
// matters most on VO destruction.
if (pthread_equal(ctx->vo->in->thread, pthread_self())) {
vo_thread_free(ctx);
} else {
mp_dispatch_run(ctx->vo->in->dispatch, vo_thread_free, ctx);
}
}
struct get_image_cmd {
struct vo *vo;
int imgfmt, w, h, stride_align;
struct mp_image *res;
};
static void sync_get_image(void *ptr)
{
struct get_image_cmd *cmd = ptr;
struct vo *vo = cmd->vo;
cmd->res = vo->driver->get_image(vo, cmd->imgfmt, cmd->w, cmd->h,
cmd->stride_align);
if (!cmd->res)
return;
// We require exactly 1 AVBufferRef.
assert(cmd->res->bufs[0]);
assert(!cmd->res->bufs[1]);
// Apply some magic to get it free'd on the VO thread as well. For this to
// work, we create a dummy-ref that aliases the original ref, which is why
// the original ref must be writable in the first place. (A newly allocated
// image should be always writable of course.)
assert(mp_image_is_writeable(cmd->res));
struct free_dr_context *ctx = talloc_zero(NULL, struct free_dr_context);
*ctx = (struct free_dr_context){
.vo = vo,
.ref = cmd->res->bufs[0],
};
AVBufferRef *new_ref = av_buffer_create(ctx->ref->data, ctx->ref->size,
free_dr_buffer_on_vo_thread, ctx, 0);
if (!new_ref)
abort(); // tiny malloc OOM
cmd->res->bufs[0] = new_ref;
atomic_fetch_add(&vo->in->dr_in_flight, 1);
}
struct mp_image *vo_get_image(struct vo *vo, int imgfmt, int w, int h,
int stride_align)
{
if (!vo->driver->get_image)
return NULL;
struct get_image_cmd cmd = {
.vo = vo,
.imgfmt = imgfmt, .w = w, .h = h, .stride_align = stride_align,
};
mp_dispatch_run(vo->in->dispatch, sync_get_image, &cmd);
return cmd.res;
}

8
video/out/vo.h
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@ -327,6 +327,14 @@ struct vo_driver {
struct mp_image *(*get_image)(struct vo *vo, int imgfmt, int w, int h,
int stride_align);
/*
* Thread-safe variant of get_image. Set at most one of these callbacks.
* This excludes _all_ synchronization magic. The only guarantee is that
* vo_driver.uninit is not called before this function returns.
*/
struct mp_image *(*get_image_ts)(struct vo *vo, int imgfmt, int w, int h,
int stride_align);
/*
* Render the given frame to the VO's backbuffer. This operation will be
* followed by a draw_osd and a flip_page[_timed] call.

1
wscript_build.py
View File

@ -428,6 +428,7 @@ def build(ctx):
( "video/out/d3d11/hwdec_dxva2dxgi.c", "d3d11 && d3d9-hwaccel" ),
( "video/out/d3d11/ra_d3d11.c", "d3d11" ),
( "video/out/dither.c" ),
( "video/out/dr_helper.c" ),
( "video/out/drm_atomic.c", "drm" ),
( "video/out/drm_common.c", "drm" ),
( "video/out/drm_prime.c", "drm && drmprime" ),