avcodec/libjxl: add Jpeg XL decoding via libjxl

This commit adds decoding support to libavcodec
for Jpeg XL images via the external library libjxl.

1 files changed, 70 insertions, 0 deletions

diff --git a/libavcodec/libjxl.c b/libavcodec/libjxl.c
new file mode 100644
index 0000000000..204d91d8a8
--- /dev/null
+++ b/libavcodec/libjxl.c
@@ -0,0 +1,70 @@
+/*
+ * JPEG XL de/encoding via libjxl, common support implementation
+ * Copyright (c) 2021 Leo Izen <leo.izen@gmail.com>
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * JPEG XL via libjxl common support implementation
+ */
+
+#include "libavutil/cpu.h"
+#include "libavutil/mem.h"
+
+#include <jxl/memory_manager.h>
+#include "libjxl.h"
+
+size_t ff_libjxl_get_threadcount(int threads)
+{
+    if (threads <= 0)
+        return av_cpu_count();
+    if (threads == 1)
+        return 0;
+    return threads;
+}
+
+/**
+ * Wrapper around av_malloc used as a jpegxl_alloc_func.
+ *
+ * @param  opaque opaque pointer for jpegxl_alloc_func, always ignored
+ * @param  size Size in bytes for the memory block to be allocated
+ * @return Pointer to the allocated block, or `NULL` if it cannot be allocated
+ */
+static void *libjxl_av_malloc(void *opaque, size_t size)
+{
+    return av_malloc(size);
+}
+
+/**
+ * Wrapper around av_free used as a jpegxl_free_func.
+ *
+ * @param opaque  opaque pointer for jpegxl_free_func, always ignored
+ * @param address Pointer to the allocated block, to free. `NULL` permitted as a no-op.
+ */
+static void libjxl_av_free(void *opaque, void *address)
+{
+    av_free(address);
+}
+
+void ff_libjxl_init_memory_manager(JxlMemoryManager *manager)
+{
+    manager->opaque = NULL;
+    manager->alloc = &libjxl_av_malloc;
+    manager->free = &libjxl_av_free;
+}