diff --git a/libavutil/Makefile b/libavutil/Makefile
index b2662c843e875b3b85c16df6c9050b0d64439a44..e45871fd1116fa723b87cb681a0356f67ef3f2c6 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -142,6 +142,7 @@ OBJS = adler32.o \
samplefmt.o \
sha.o \
sha512.o \
+ slicethread.o \
spherical.o \
stereo3d.o \
threadmessage.o \
diff --git a/libavutil/slicethread.c b/libavutil/slicethread.c
new file mode 100644
index 0000000000000000000000000000000000000000..c43f87a2aa4aa4f0fcbb1eba5f7ab8710ee5f9bd
--- /dev/null
+++ b/libavutil/slicethread.c
@@ -0,0 +1,259 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdatomic.h>
+#include "slicethread.h"
+#include "mem.h"
+#include "thread.h"
+#include "avassert.h"
+
+#if HAVE_PTHREADS || HAVE_W32THREADS || HAVE_OS2THREADS
+
+typedef struct WorkerContext {
+ AVSliceThread *ctx;
+ pthread_mutex_t mutex;
+ pthread_cond_t cond;
+ pthread_t thread;
+ int done;
+} WorkerContext;
+
+struct AVSliceThread {
+ WorkerContext *workers;
+ int nb_threads;
+ int nb_active_threads;
+ int nb_jobs;
+
+ atomic_uint first_job;
+ atomic_uint current_job;
+ pthread_mutex_t done_mutex;
+ pthread_cond_t done_cond;
+ int done;
+ int finished;
+
+ void *priv;
+ void (*worker_func)(void *priv, int jobnr, int threadnr, int nb_jobs, int nb_threads);
+ void (*main_func)(void *priv);
+};
+
+static int run_jobs(AVSliceThread *ctx)
+{
+ unsigned nb_jobs = ctx->nb_jobs;
+ unsigned nb_active_threads = ctx->nb_active_threads;
+ unsigned first_job = atomic_fetch_add_explicit(&ctx->first_job, 1, memory_order_acq_rel);
+ unsigned current_job = first_job;
+
+ do {
+ ctx->worker_func(ctx->priv, current_job, first_job, nb_jobs, nb_active_threads);
+ } while ((current_job = atomic_fetch_add_explicit(&ctx->current_job, 1, memory_order_acq_rel)) < nb_jobs);
+
+ return current_job == nb_jobs + nb_active_threads - 1;
+}
+
+static void *attribute_align_arg thread_worker(void *v)
+{
+ WorkerContext *w = v;
+ AVSliceThread *ctx = w->ctx;
+
+ pthread_mutex_lock(&w->mutex);
+ pthread_cond_signal(&w->cond);
+
+ while (1) {
+ w->done = 1;
+ while (w->done)
+ pthread_cond_wait(&w->cond, &w->mutex);
+
+ if (ctx->finished) {
+ pthread_mutex_unlock(&w->mutex);
+ return NULL;
+ }
+
+ if (run_jobs(ctx)) {
+ pthread_mutex_lock(&ctx->done_mutex);
+ ctx->done = 1;
+ pthread_cond_signal(&ctx->done_cond);
+ pthread_mutex_unlock(&ctx->done_mutex);
+ }
+ }
+}
+
+int avpriv_slicethread_create(AVSliceThread **pctx, void *priv,
+ void (*worker_func)(void *priv, int jobnr, int threadnr, int nb_jobs, int nb_threads),
+ void (*main_func)(void *priv),
+ int nb_threads)
+{
+ AVSliceThread *ctx;
+ int nb_workers, i;
+
+#if HAVE_W32THREADS
+ w32thread_init();
+#endif
+
+ av_assert0(nb_threads >= 0);
+ if (!nb_threads) {
+ int nb_cpus = av_cpu_count();
+ if (nb_cpus > 1)
+ nb_threads = nb_cpus + 1;
+ else
+ nb_threads = 1;
+ }
+
+ nb_workers = nb_threads;
+ if (!main_func)
+ nb_workers--;
+
+ *pctx = ctx = av_mallocz(sizeof(*ctx));
+ if (!ctx)
+ return AVERROR(ENOMEM);
+
+ if (nb_workers && !(ctx->workers = av_calloc(nb_workers, sizeof(*ctx->workers)))) {
+ av_freep(pctx);
+ return AVERROR(ENOMEM);
+ }
+
+ ctx->priv = priv;
+ ctx->worker_func = worker_func;
+ ctx->main_func = main_func;
+ ctx->nb_threads = nb_threads;
+ ctx->nb_active_threads = 0;
+ ctx->nb_jobs = 0;
+ ctx->finished = 0;
+
+ atomic_init(&ctx->first_job, 0);
+ atomic_init(&ctx->current_job, 0);
+ pthread_mutex_init(&ctx->done_mutex, NULL);
+ pthread_cond_init(&ctx->done_cond, NULL);
+ ctx->done = 0;
+
+ for (i = 0; i < nb_workers; i++) {
+ WorkerContext *w = &ctx->workers[i];
+ int ret;
+ w->ctx = ctx;
+ pthread_mutex_init(&w->mutex, NULL);
+ pthread_cond_init(&w->cond, NULL);
+ pthread_mutex_lock(&w->mutex);
+ w->done = 0;
+
+ if (ret = pthread_create(&w->thread, NULL, thread_worker, w)) {
+ ctx->nb_threads = main_func ? i : i + 1;
+ pthread_mutex_unlock(&w->mutex);
+ pthread_cond_destroy(&w->cond);
+ pthread_mutex_destroy(&w->mutex);
+ avpriv_slicethread_free(pctx);
+ return AVERROR(ret);
+ }
+
+ while (!w->done)
+ pthread_cond_wait(&w->cond, &w->mutex);
+ pthread_mutex_unlock(&w->mutex);
+ }
+
+ return nb_threads;
+}
+
+void avpriv_slicethread_execute(AVSliceThread *ctx, int nb_jobs, int execute_main)
+{
+ int nb_workers, i, is_last = 0;
+
+ av_assert0(nb_jobs > 0);
+ ctx->nb_jobs = nb_jobs;
+ ctx->nb_active_threads = FFMIN(nb_jobs, ctx->nb_threads);
+ atomic_store_explicit(&ctx->first_job, 0, memory_order_relaxed);
+ atomic_store_explicit(&ctx->current_job, ctx->nb_active_threads, memory_order_relaxed);
+ nb_workers = ctx->nb_active_threads;
+ if (!ctx->main_func || !execute_main)
+ nb_workers--;
+
+ for (i = 0; i < nb_workers; i++) {
+ WorkerContext *w = &ctx->workers[i];
+ pthread_mutex_lock(&w->mutex);
+ w->done = 0;
+ pthread_cond_signal(&w->cond);
+ pthread_mutex_unlock(&w->mutex);
+ }
+
+ if (ctx->main_func && execute_main)
+ ctx->main_func(ctx->priv);
+ else
+ is_last = run_jobs(ctx);
+
+ if (!is_last) {
+ pthread_mutex_lock(&ctx->done_mutex);
+ while (!ctx->done)
+ pthread_cond_wait(&ctx->done_cond, &ctx->done_mutex);
+ ctx->done = 0;
+ pthread_mutex_unlock(&ctx->done_mutex);
+ }
+}
+
+void avpriv_slicethread_free(AVSliceThread **pctx)
+{
+ AVSliceThread *ctx;
+ int nb_workers, i;
+
+ if (!pctx || !*pctx)
+ return;
+
+ ctx = *pctx;
+ nb_workers = ctx->nb_threads;
+ if (!ctx->main_func)
+ nb_workers--;
+
+ ctx->finished = 1;
+ for (i = 0; i < nb_workers; i++) {
+ WorkerContext *w = &ctx->workers[i];
+ pthread_mutex_lock(&w->mutex);
+ w->done = 0;
+ pthread_cond_signal(&w->cond);
+ pthread_mutex_unlock(&w->mutex);
+ }
+
+ for (i = 0; i < nb_workers; i++) {
+ WorkerContext *w = &ctx->workers[i];
+ pthread_join(w->thread, NULL);
+ pthread_cond_destroy(&w->cond);
+ pthread_mutex_destroy(&w->mutex);
+ }
+
+ pthread_cond_destroy(&ctx->done_cond);
+ pthread_mutex_destroy(&ctx->done_mutex);
+ av_freep(&ctx->workers);
+ av_freep(pctx);
+}
+
+#else /* HAVE_PTHREADS || HAVE_W32THREADS || HAVE_OS32THREADS */
+
+int avpriv_slicethread_create(AVSliceThread **pctx, void *priv,
+ void (*worker_func)(void *priv, int jobnr, int threadnr, int nb_jobs, int nb_threads),
+ void (*main_func)(void *priv),
+ int nb_threads)
+{
+ *pctx = NULL;
+ return AVERROR(EINVAL);
+}
+
+void avpriv_slicethread_execute(AVSliceThread *ctx, int nb_jobs, int execute_main)
+{
+ av_assert0(0);
+}
+
+void avpriv_slicethread_free(AVSliceThread **pctx)
+{
+ av_assert0(!pctx || !*pctx);
+}
+
+#endif /* HAVE_PTHREADS || HAVE_W32THREADS || HAVE_OS32THREADS */
diff --git a/libavutil/slicethread.h b/libavutil/slicethread.h
new file mode 100644
index 0000000000000000000000000000000000000000..f6f6f302c444be69bf85976f3ba608ff0c52d5df
--- /dev/null
+++ b/libavutil/slicethread.h
@@ -0,0 +1,52 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_SLICETHREAD_H
+#define AVUTIL_SLICETHREAD_H
+
+typedef struct AVSliceThread AVSliceThread;
+
+/**
+ * Create slice threading context.
+ * @param pctx slice threading context returned here
+ * @param priv private pointer to be passed to callback function
+ * @param worker_func callback function to be executed
+ * @param main_func special callback function, called from main thread, may be NULL
+ * @param nb_threads number of threads, 0 for automatic, must be >= 0
+ * @return return number of threads or negative AVERROR on failure
+ */
+int avpriv_slicethread_create(AVSliceThread **pctx, void *priv,
+ void (*worker_func)(void *priv, int jobnr, int threadnr, int nb_jobs, int nb_threads),
+ void (*main_func)(void *priv),
+ int nb_threads);
+
+/**
+ * Execute slice threading.
+ * @param ctx slice threading context
+ * @param nb_jobs number of jobs, must be > 0
+ * @param execute_main also execute main_func
+ */
+void avpriv_slicethread_execute(AVSliceThread *ctx, int nb_jobs, int execute_main);
+
+/**
+ * Destroy slice threading context.
+ * @param pctx pointer to context
+ */
+void avpriv_slicethread_free(AVSliceThread **pctx);
+
+#endif
diff --git a/libavutil/version.h b/libavutil/version.h
index f752ddb044e96f09b3a2055effe5ffc7d201352d..d4f9335a2fdea412eb598567eb496479b35ef4f2 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -80,7 +80,7 @@
#define LIBAVUTIL_VERSION_MAJOR 55
-#define LIBAVUTIL_VERSION_MINOR 67
+#define LIBAVUTIL_VERSION_MINOR 68
#define LIBAVUTIL_VERSION_MICRO 100
#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \