Add scripts to compile FFmpeg to WASI

.gitignore

@@ -1 +1,4 @@
 wasi-sdk
+build
+
+*.wasm

.gitmodules

@@ -1,3 +1,9 @@
 [submodule "FFmpeg"]
 	path = FFmpeg
 	url = https://github.com/FFmpeg/FFmpeg.git
+[submodule "deps/zlib"]
+	path = deps/zlib
+	url = https://github.com/madler/zlib.git
+[submodule "deps/x264"]
+	path = deps/x264
+	url = https://github.com/ffmpegwasm/x264.git

patches/file_open.c

@@ -0,0 +1,198 @@
+/*
+ * 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 "config.h"
+#include "internal.h"
+#include "mem.h"
+#include <stdarg.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#if HAVE_IO_H
+#include <io.h>
+#endif
+
+#ifdef _WIN32
+#undef open
+#undef lseek
+#undef stat
+#undef fstat
+#include <windows.h>
+#include <share.h>
+#include <errno.h>
+#include "wchar_filename.h"
+
+static int win32_open(const char *filename_utf8, int oflag, int pmode)
+{
+    int fd;
+    wchar_t *filename_w;
+
+    /* convert UTF-8 to wide chars */
+    if (get_extended_win32_path(filename_utf8, &filename_w))
+        return -1;
+    if (!filename_w)
+        goto fallback;
+
+    fd = _wsopen(filename_w, oflag, SH_DENYNO, pmode);
+    av_freep(&filename_w);
+
+    if (fd != -1 || (oflag & O_CREAT))
+        return fd;
+
+fallback:
+    /* filename may be in CP_ACP */
+    return _sopen(filename_utf8, oflag, SH_DENYNO, pmode);
+}
+#define open win32_open
+#endif
+
+int avpriv_open(const char *filename, int flags, ...)
+{
+    int fd;
+    unsigned int mode = 0;
+    va_list ap;
+
+    va_start(ap, flags);
+    if (flags & O_CREAT)
+        mode = va_arg(ap, unsigned int);
+    va_end(ap);
+
+#ifdef O_CLOEXEC
+    flags |= O_CLOEXEC;
+#endif
+#ifdef O_NOINHERIT
+    flags |= O_NOINHERIT;
+#endif
+
+    fd = open(filename, flags, mode);
+#if HAVE_FCNTL
+    if (fd != -1) {
+        if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
+            av_log(NULL, AV_LOG_DEBUG, "Failed to set close on exec\n");
+    }
+#endif
+
+    return fd;
+}
+
+typedef struct FileLogContext {
+    const AVClass *class;
+    int   log_offset;
+    void *log_ctx;
+} FileLogContext;
+
+static const AVClass file_log_ctx_class = {
+    .class_name                = "TEMPFILE",
+    .item_name                 = av_default_item_name,
+    .option                    = NULL,
+    .version                   = LIBAVUTIL_VERSION_INT,
+    .log_level_offset_offset   = offsetof(FileLogContext, log_offset),
+    .parent_log_context_offset = offsetof(FileLogContext, log_ctx),
+};
+
+int avpriv_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx)
+{
+    FileLogContext file_log_ctx = { &file_log_ctx_class, log_offset, log_ctx };
+    int fd = -1;
+#if !HAVE_MKSTEMP
+    // void *ptr= tempnam(NULL, prefix);
+    // if(!ptr)
+    //     ptr= tempnam(".", prefix);
+    void *ptr = NULL;
+    *filename = av_strdup(ptr);
+#undef free
+    free(ptr);
+#else
+    size_t len = strlen(prefix) + 12; /* room for "/tmp/" and "XXXXXX\0" */
+    *filename  = av_malloc(len);
+#endif
+    /* -----common section-----*/
+    if (!*filename) {
+        av_log(&file_log_ctx, AV_LOG_ERROR, "ff_tempfile: Cannot allocate file name\n");
+        return AVERROR(ENOMEM);
+    }
+#if !HAVE_MKSTEMP
+#   ifndef O_BINARY
+#       define O_BINARY 0
+#   endif
+#   ifndef O_EXCL
+#       define O_EXCL 0
+#   endif
+    fd = open(*filename, O_RDWR | O_BINARY | O_CREAT | O_EXCL, 0600);
+#else
+    snprintf(*filename, len, "/tmp/%sXXXXXX", prefix);
+    fd = mkstemp(*filename);
+#if defined(_WIN32) || defined (__ANDROID__) || defined(__DJGPP__)
+    if (fd < 0) {
+        snprintf(*filename, len, "./%sXXXXXX", prefix);
+        fd = mkstemp(*filename);
+    }
+#endif
+#endif
+    /* -----common section-----*/
+    if (fd < 0) {
+        int err = AVERROR(errno);
+        av_log(&file_log_ctx, AV_LOG_ERROR, "ff_tempfile: Cannot open temporary file %s\n", *filename);
+        av_freep(filename);
+        return err;
+    }
+    return fd; /* success */
+}
+
+FILE *avpriv_fopen_utf8(const char *path, const char *mode)
+{
+    int fd;
+    int access;
+    const char *m = mode;
+
+    switch (*m++) {
+    case 'r': access = O_RDONLY; break;
+    case 'w': access = O_CREAT|O_WRONLY|O_TRUNC; break;
+    case 'a': access = O_CREAT|O_WRONLY|O_APPEND; break;
+    default :
+        errno = EINVAL;
+        return NULL;
+    }
+    while (*m) {
+        if (*m == '+') {
+            access &= ~(O_RDONLY | O_WRONLY);
+            access |= O_RDWR;
+        } else if (*m == 'b') {
+#ifdef O_BINARY
+            access |= O_BINARY;
+#endif
+        } else if (*m) {
+            errno = EINVAL;
+            return NULL;
+        }
+        m++;
+    }
+    fd = avpriv_open(path, access, 0666);
+    if (fd == -1)
+        return NULL;
+    return fdopen(fd, mode);
+}
+
+#if FF_API_AV_FOPEN_UTF8
+FILE *av_fopen_utf8(const char *path, const char *mode)
+{
+    return avpriv_fopen_utf8(path, mode);
+}
+#endif

scripts/build-deps.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+set -euo pipefail
+
+for f in ./scripts/deps/*.sh; do
+  bash "$f" 
+done

scripts/build.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -euo pipefail
+
+cd FFmpeg
+cp ../patches/file_open.c ./libavutil/file_open.c
+../build/compile.sh
+cp ffmpeg ../ffmpeg.wasm
+cp ffprobe ../ffprobe.wasm
+git reset --hard
+cd ..

scripts/configure.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+
+set -euo pipefail
+
+FFMPEG_CONFIG_FLAGS_BASE=(
+  --target-os=none        # use none to prevent any os specific configurations
+  --arch=x86_32           # use x86_32 to achieve minimal architectural optimization
+  --enable-cross-compile  # enable cross compile
+  --disable-x86asm        # disable x86 asm
+  --disable-inline-asm    # disable inline asm
+  --disable-stripping     # disable stripping
+  --disable-doc           # disable doc
+  --disable-debug         # disable debug info, required by closure
+  --disable-runtime-cpudetect   # disable runtime cpu detect
+  --disable-autodetect    # disable external libraries auto detect
+  --disable-network       # https://github.com/WebAssembly/wasi-sdk/issues/112
+  # --enable-lto            # use link-time optimization
+  --disable-pthreads
+  --disable-w32threads
+  --disable-os2threads
+  --pkg-config-flags="--static"
+  --nm=../wasi-sdk/bin/nm
+  --ar=../wasi-sdk/bin/ar
+  --ranlib=../wasi-sdk/bin/ranlib
+  --cc=../wasi-sdk/bin/clang
+  --cxx=../wasi-sdk/bin/clang++
+  --objcc=../wasi-sdk/bin/clang
+  --dep-cc=../wasi-sdk/bin/clang
+  --enable-gpl
+  --enable-libx264
+  --enable-zlib
+  --extra-cflags="-I../build/include"
+  --extra-ldflags="-L../build/lib"
+  --enable-encoder=libx264
+  --enable-encoder=png
+)
+
+mkdir -p build
+
+cd FFmpeg
+./configure ${FFMPEG_CONFIG_FLAGS_BASE[@]}
+
+make -n |
+  sed 's/clang /clang -D_WASI_EMULATED_PROCESS_CLOCKS -lwasi-emulated-process-clocks /g' |
+  sed 's/clang /clang -D_WASI_EMULATED_SIGNAL -lwasi-emulated-signal /g' |
+  cat > ../build/compile.sh
+chmod +x ../build/compile.sh
+cd ..

scripts/deps/x264.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+set -euo pipefail
+
+cd deps/x264
+CC=../../wasi-sdk/bin/clang \
+    AR=../../wasi-sdk/bin/ar \
+    RANLIB=../../wasi-sdk/bin/ranlib \
+    ./configure \
+    --prefix=../../build \
+    --host=i686-gnu \
+    --enable-static \
+    --disable-cli \
+    --disable-asm \
+    --disable-thread \
+    --extra-cflags="-D_WASI_EMULATED_SIGNAL" \
+    --extra-ldflags="-lwasi-emulated-signal"
+sed -i 's/#define HAVE_MALLOC_H 1/#define HAVE_MALLOC_H 0/g' config.h
+make install-lib-static
+cd ../..

scripts/deps/zlib.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+set -euo pipefail
+
+cd deps/zlib
+CC=../../wasi-sdk/bin/clang \
+    AR=../../wasi-sdk/bin/ar \
+    RANLIB=../../wasi-sdk/bin/ranlib \
+    prefix=../../build \
+    ./configure --static
+make install
+git reset --hard
+cd ../..

install.sh → scripts/install.sh

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -euo pipefail
+
 WASI_VERSION=16
 WASI_VERSION_FULL=${WASI_VERSION}.0
 wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_VERSION}/wasi-sdk-${WASI_VERSION_FULL}-linux.tar.gz