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mpv/video/mp_image_pool.c
wm4 95e13e3d3e mp_image_pool: expose a function for reporting hw download format
Basically predicts what mp_image_hw_download() will do. It's pretty
simple if it gets the full mp_image. (Taking just a imgfmt would make
this pretty hard/impossible or inaccurate.)

Used in one of the following commits.
2019-10-02 21:07:14 +02:00

429 lines
13 KiB
C

/*
* This file is part of mpv.
*
* 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/>.
*/
#include "config.h"
#include <stddef.h>
#include <stdbool.h>
#include <pthread.h>
#include <assert.h>
#include <libavutil/buffer.h>
#include <libavutil/hwcontext.h>
#include <libavutil/mem.h>
#include "mpv_talloc.h"
#include "common/common.h"
#include "fmt-conversion.h"
#include "mp_image.h"
#include "mp_image_pool.h"
static pthread_mutex_t pool_mutex = PTHREAD_MUTEX_INITIALIZER;
#define pool_lock() pthread_mutex_lock(&pool_mutex)
#define pool_unlock() pthread_mutex_unlock(&pool_mutex)
// Thread-safety: the pool itself is not thread-safe, but pool-allocated images
// can be referenced and unreferenced from other threads. (As long as the image
// destructors are thread-safe.)
struct mp_image_pool {
struct mp_image **images;
int num_images;
int fmt, w, h;
mp_image_allocator allocator;
void *allocator_ctx;
bool use_lru;
unsigned int lru_counter;
};
// Used to gracefully handle the case when the pool is freed while image
// references allocated from the image pool are still held by someone.
struct image_flags {
// If both of these are false, the image must be freed.
bool referenced; // outside mp_image reference exists
bool pool_alive; // the mp_image_pool references this
unsigned int order; // for LRU allocation (basically a timestamp)
};
static void image_pool_destructor(void *ptr)
{
struct mp_image_pool *pool = ptr;
mp_image_pool_clear(pool);
}
// If tparent!=NULL, set it as talloc parent for the pool.
struct mp_image_pool *mp_image_pool_new(void *tparent)
{
struct mp_image_pool *pool = talloc_ptrtype(tparent, pool);
talloc_set_destructor(pool, image_pool_destructor);
*pool = (struct mp_image_pool) {0};
return pool;
}
void mp_image_pool_clear(struct mp_image_pool *pool)
{
for (int n = 0; n < pool->num_images; n++) {
struct mp_image *img = pool->images[n];
struct image_flags *it = img->priv;
bool referenced;
pool_lock();
assert(it->pool_alive);
it->pool_alive = false;
referenced = it->referenced;
pool_unlock();
if (!referenced)
talloc_free(img);
}
pool->num_images = 0;
}
// This is the only function that is allowed to run in a different thread.
// (Consider passing an image to another thread, which frees it.)
static void unref_image(void *opaque, uint8_t *data)
{
struct mp_image *img = opaque;
struct image_flags *it = img->priv;
bool alive;
pool_lock();
assert(it->referenced);
it->referenced = false;
alive = it->pool_alive;
pool_unlock();
if (!alive)
talloc_free(img);
}
// Return a new image of given format/size. Unlike mp_image_pool_get(), this
// returns NULL if there is no free image of this format/size.
struct mp_image *mp_image_pool_get_no_alloc(struct mp_image_pool *pool, int fmt,
int w, int h)
{
struct mp_image *new = NULL;
pool_lock();
for (int n = 0; n < pool->num_images; n++) {
struct mp_image *img = pool->images[n];
struct image_flags *img_it = img->priv;
assert(img_it->pool_alive);
if (!img_it->referenced) {
if (img->imgfmt == fmt && img->w == w && img->h == h) {
if (pool->use_lru) {
struct image_flags *new_it = new ? new->priv : NULL;
if (!new_it || new_it->order > img_it->order)
new = img;
} else {
new = img;
break;
}
}
}
}
pool_unlock();
if (!new)
return NULL;
// Reference the new image. Since mp_image_pool is not declared thread-safe,
// and unreffing images from other threads does not allocate new images,
// no synchronization is required here.
for (int p = 0; p < MP_MAX_PLANES; p++)
assert(!!new->bufs[p] == !p); // only 1 AVBufferRef
struct mp_image *ref = mp_image_new_dummy_ref(new);
// This assumes the buffer is at this point exclusively owned by us: we
// can't track whether the buffer is unique otherwise.
// (av_buffer_is_writable() checks the refcount of the new buffer only.)
int flags = av_buffer_is_writable(new->bufs[0]) ? 0 : AV_BUFFER_FLAG_READONLY;
ref->bufs[0] = av_buffer_create(new->bufs[0]->data, new->bufs[0]->size,
unref_image, new, flags);
if (!ref->bufs[0]) {
talloc_free(ref);
return NULL;
}
struct image_flags *it = new->priv;
assert(!it->referenced && it->pool_alive);
it->referenced = true;
it->order = ++pool->lru_counter;
return ref;
}
void mp_image_pool_add(struct mp_image_pool *pool, struct mp_image *new)
{
struct image_flags *it = talloc_ptrtype(new, it);
*it = (struct image_flags) { .pool_alive = true };
new->priv = it;
MP_TARRAY_APPEND(pool, pool->images, pool->num_images, new);
}
// Return a new image of given format/size. The only difference to
// mp_image_alloc() is that there is a transparent mechanism to recycle image
// data allocations through this pool.
// If pool==NULL, mp_image_alloc() is called (for convenience).
// The image can be free'd with talloc_free().
// Returns NULL on OOM.
struct mp_image *mp_image_pool_get(struct mp_image_pool *pool, int fmt,
int w, int h)
{
if (!pool)
return mp_image_alloc(fmt, w, h);
struct mp_image *new = mp_image_pool_get_no_alloc(pool, fmt, w, h);
if (!new) {
if (fmt != pool->fmt || w != pool->w || h != pool->h)
mp_image_pool_clear(pool);
pool->fmt = fmt;
pool->w = w;
pool->h = h;
if (pool->allocator) {
new = pool->allocator(pool->allocator_ctx, fmt, w, h);
} else {
new = mp_image_alloc(fmt, w, h);
}
if (!new)
return NULL;
mp_image_pool_add(pool, new);
new = mp_image_pool_get_no_alloc(pool, fmt, w, h);
}
return new;
}
// Like mp_image_new_copy(), but allocate the image out of the pool.
// If pool==NULL, a plain copy is made (for convenience).
// Returns NULL on OOM.
struct mp_image *mp_image_pool_new_copy(struct mp_image_pool *pool,
struct mp_image *img)
{
struct mp_image *new = mp_image_pool_get(pool, img->imgfmt, img->w, img->h);
if (new) {
mp_image_copy(new, img);
mp_image_copy_attributes(new, img);
}
return new;
}
// Like mp_image_make_writeable(), but if a copy has to be made, allocate it
// out of the pool.
// If pool==NULL, mp_image_make_writeable() is called (for convenience).
// Returns false on failure (see mp_image_make_writeable()).
bool mp_image_pool_make_writeable(struct mp_image_pool *pool,
struct mp_image *img)
{
if (mp_image_is_writeable(img))
return true;
struct mp_image *new = mp_image_pool_new_copy(pool, img);
if (!new)
return false;
mp_image_steal_data(img, new);
assert(mp_image_is_writeable(img));
return true;
}
// Call cb(cb_data, fmt, w, h) to allocate an image. Note that the resulting
// image must use only 1 AVBufferRef. The returned image must also be owned
// exclusively by the image pool, otherwise mp_image_is_writeable() will not
// work due to FFmpeg restrictions.
void mp_image_pool_set_allocator(struct mp_image_pool *pool,
mp_image_allocator cb, void *cb_data)
{
pool->allocator = cb;
pool->allocator_ctx = cb_data;
}
// Put into LRU mode. (Likely better for hwaccel surfaces, but worse for memory.)
void mp_image_pool_set_lru(struct mp_image_pool *pool)
{
pool->use_lru = true;
}
// Return the sw image format mp_image_hw_download() would use. This can be
// different from src->params.hw_subfmt in obscure cases.
int mp_image_hw_download_get_sw_format(struct mp_image *src)
{
if (!src->hwctx)
return 0;
// Try to find the first format which we can apparently use.
int imgfmt = 0;
enum AVPixelFormat *fmts;
if (av_hwframe_transfer_get_formats(src->hwctx,
AV_HWFRAME_TRANSFER_DIRECTION_FROM, &fmts, 0) < 0)
return 0;
for (int n = 0; fmts[n] != AV_PIX_FMT_NONE; n++) {
imgfmt = pixfmt2imgfmt(fmts[n]);
if (imgfmt)
break;
}
av_free(fmts);
return imgfmt;
}
// Copies the contents of the HW surface src to system memory and retuns it.
// If swpool is not NULL, it's used to allocate the target image.
// src must be a hw surface with a AVHWFramesContext attached.
// The returned image is cropped as needed.
// Returns NULL on failure.
struct mp_image *mp_image_hw_download(struct mp_image *src,
struct mp_image_pool *swpool)
{
int imgfmt = mp_image_hw_download_get_sw_format(src);
if (!imgfmt)
return NULL;
assert(src->hwctx);
AVHWFramesContext *fctx = (void *)src->hwctx->data;
struct mp_image *dst =
mp_image_pool_get(swpool, imgfmt, fctx->width, fctx->height);
if (!dst)
return NULL;
// Target image must be writable, so unref it.
AVFrame *dstav = mp_image_to_av_frame_and_unref(dst);
if (!dstav)
return NULL;
AVFrame *srcav = mp_image_to_av_frame(src);
if (!srcav) {
av_frame_unref(dstav);
return NULL;
}
int res = av_hwframe_transfer_data(dstav, srcav, 0);
av_frame_free(&srcav);
dst = mp_image_from_av_frame(dstav);
av_frame_free(&dstav);
if (res >= 0 && dst) {
mp_image_set_size(dst, src->w, src->h);
mp_image_copy_attributes(dst, src);
} else {
mp_image_unrefp(&dst);
}
return dst;
}
bool mp_image_hw_upload(struct mp_image *hw_img, struct mp_image *src)
{
if (hw_img->w != src->w || hw_img->h != src->h)
return false;
if (!hw_img->hwctx || src->hwctx)
return false;
bool ok = false;
AVFrame *dstav = NULL;
AVFrame *srcav = NULL;
// This means the destination image will not be "writable", which would be
// a pain if Libav enforced this - fortunately it doesn't care. We can
// transfer data to it even if there are multiple refs.
dstav = mp_image_to_av_frame(hw_img);
if (!dstav)
goto done;
srcav = mp_image_to_av_frame(src);
if (!srcav)
goto done;
ok = av_hwframe_transfer_data(dstav, srcav, 0) >= 0;
done:
av_frame_unref(srcav);
av_frame_unref(dstav);
if (ok)
mp_image_copy_attributes(hw_img, src);
return ok;
}
bool mp_update_av_hw_frames_pool(struct AVBufferRef **hw_frames_ctx,
struct AVBufferRef *hw_device_ctx,
int imgfmt, int sw_imgfmt, int w, int h)
{
enum AVPixelFormat format = imgfmt2pixfmt(imgfmt);
enum AVPixelFormat sw_format = imgfmt2pixfmt(sw_imgfmt);
if (format == AV_PIX_FMT_NONE || sw_format == AV_PIX_FMT_NONE ||
!hw_device_ctx || w < 1 || h < 1)
{
av_buffer_unref(hw_frames_ctx);
return false;
}
if (*hw_frames_ctx) {
AVHWFramesContext *hw_frames = (void *)(*hw_frames_ctx)->data;
if (hw_frames->device_ref->data != hw_device_ctx->data ||
hw_frames->format != format || hw_frames->sw_format != sw_format ||
hw_frames->width != w || hw_frames->height != h)
av_buffer_unref(hw_frames_ctx);
}
if (!*hw_frames_ctx) {
*hw_frames_ctx = av_hwframe_ctx_alloc(hw_device_ctx);
if (!*hw_frames_ctx)
return false;
AVHWFramesContext *hw_frames = (void *)(*hw_frames_ctx)->data;
hw_frames->format = format;
hw_frames->sw_format = sw_format;
hw_frames->width = w;
hw_frames->height = h;
if (av_hwframe_ctx_init(*hw_frames_ctx) < 0) {
av_buffer_unref(hw_frames_ctx);
return false;
}
}
return true;
}
struct mp_image *mp_av_pool_image_hw_upload(struct AVBufferRef *hw_frames_ctx,
struct mp_image *src)
{
AVFrame *av_frame = av_frame_alloc();
if (!av_frame)
return NULL;
if (av_hwframe_get_buffer(hw_frames_ctx, av_frame, 0) < 0) {
av_frame_free(&av_frame);
return NULL;
}
struct mp_image *dst = mp_image_from_av_frame(av_frame);
av_frame_free(&av_frame);
if (!dst)
return NULL;
if (dst->w < src->w || dst->h < src->h) {
talloc_free(dst);
return NULL;
}
mp_image_set_size(dst, src->w, src->h);
if (!mp_image_hw_upload(dst, src)) {
talloc_free(dst);
return NULL;
}
mp_image_copy_attributes(dst, src);
return dst;
}