From 4739b0c97b3378bdaf737171777fe9a71a53eff1 Mon Sep 17 00:00:00 2001

From: Neal Gompa <ngompa@fedoraproject.org>

Date: Wed, 12 Oct 2022 09:41:27 -0400

Subject: [PATCH] avcodec/openh264: Add the ability to dlopen() OpenH264

​

We can't directly depend on OpenH264, but we can weakly link to it

and gracefully expose the capability.

​

Co-authored-by: Andreas Schneider <asn@cryptomilk.org>

Co-authored-by: Neal Gompa <ngompa@fedoraproject.org>

​

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>

Signed-off-by: Neal Gompa <ngompa@fedoraproject.org>

---

 configure                       |    3 

 libavcodec/Makefile             |    1 

 libavcodec/libopenh264.c        |    5 +

 libavcodec/libopenh264_dlopen.c |  147 ++++++++++++++++++++++++++++++++++++++++

 libavcodec/libopenh264_dlopen.h |   58 +++++++++++++++

 libavcodec/libopenh264dec.c     |    8 ++

 libavcodec/libopenh264enc.c     |    8 ++

 7 files changed, 230 insertions(+)

 create mode 100644 libavcodec/libopenh264_dlopen.c

 create mode 100644 libavcodec/libopenh264_dlopen.h

​

Index: ffmpeg-7.1/configure

===================================================================

--- ffmpeg-7.1.orig/configure

+++ ffmpeg-7.1/configure

@@ -255,6 +255,7 @@ External library support:

   --enable-libopencore-amrwb enable AMR-WB decoding via libopencore-amrwb [no]

   --enable-libopencv       enable video filtering via libopencv [no]

   --enable-libopenh264     enable H.264 encoding via OpenH264 [no]

+  --enable-libopenh264-dlopen  enable H.264 encoding via dlopen()'ed OpenH264 [no]

   --enable-libopenjpeg     enable JPEG 2000 encoding via OpenJPEG [no]

   --enable-libopenmpt      enable decoding tracked files via libopenmpt [no]

   --enable-libopenvino     enable OpenVINO as a DNN module backend

@@ -1939,6 +1940,7 @@ EXTERNAL_LIBRARY_LIST="

     libmysofa

     libopencv

     libopenh264

+    libopenh264_dlopen

     libopenjpeg

     libopenmpt

     libopenvino

@@ -6966,6 +6968,7 @@ enabled libopencv         && { check_hea

                                  require libopencv opencv2/core/core_c.h cvCreateImageHeader -lopencv_core -lopencv_imgproc; } ||

                                require_pkg_config libopencv opencv opencv/cxcore.h cvCreateImageHeader; }

 enabled libopenh264       && require_pkg_config libopenh264 "openh264 >= 1.3.0" wels/codec_api.h WelsGetCodecVersion

+enabled libopenh264_dlopen && enable libopenh264 && add_cppflags "-I$(dirname $(readlink -f "$0"))/ffdlopenhdrs/include -DCONFIG_LIBOPENH264_DLOPEN=1"

 enabled libopenjpeg       && { check_pkg_config libopenjpeg "libopenjp2 >= 2.1.0" openjpeg.h opj_version ||

                                { require_pkg_config libopenjpeg "libopenjp2 >= 2.1.0" openjpeg.h opj_version -DOPJ_STATIC && add_cppflags -DOPJ_STATIC; } }

 enabled libopenmpt        && require_pkg_config libopenmpt "libopenmpt >= 0.2.6557" libopenmpt/libopenmpt.h openmpt_module_create -lstdc++ && append libopenmpt_extralibs "-lstdc++"

Index: ffmpeg-7.1/libavcodec/Makefile

===================================================================

--- ffmpeg-7.1.orig/libavcodec/Makefile

+++ ffmpeg-7.1/libavcodec/Makefile

@@ -1138,6 +1138,7 @@ OBJS-$(CONFIG_LIBMP3LAME_ENCODER)

 OBJS-$(CONFIG_LIBOPENCORE_AMRNB_DECODER)  += libopencore-amr.o

 OBJS-$(CONFIG_LIBOPENCORE_AMRNB_ENCODER)  += libopencore-amr.o

 OBJS-$(CONFIG_LIBOPENCORE_AMRWB_DECODER)  += libopencore-amr.o

+OBJS-$(CONFIG_LIBOPENH264_DLOPEN)         += libopenh264_dlopen.o

 OBJS-$(CONFIG_LIBOPENH264_DECODER)        += libopenh264dec.o libopenh264.o

 OBJS-$(CONFIG_LIBOPENH264_ENCODER)        += libopenh264enc.o libopenh264.o

 OBJS-$(CONFIG_LIBOPENJPEG_ENCODER)        += libopenjpegenc.o

Index: ffmpeg-7.1/libavcodec/libopenh264.c

===================================================================

--- ffmpeg-7.1.orig/libavcodec/libopenh264.c

+++ ffmpeg-7.1/libavcodec/libopenh264.c

@@ -20,8 +20,13 @@

  */

 #include <string.h>

+

+#ifdef CONFIG_LIBOPENH264_DLOPEN

+#include "libopenh264_dlopen.h"

+#else

 #include <wels/codec_api.h>

 #include <wels/codec_ver.h>

+#endif

 #include "libavutil/error.h"

 #include "libavutil/log.h"

Index: ffmpeg-7.1/libavcodec/libopenh264_dlopen.c

===================================================================

--- /dev/null

+++ ffmpeg-7.1/libavcodec/libopenh264_dlopen.c

@@ -0,0 +1,147 @@

+/*

+ * OpenH264 dlopen code

+ *

+ * Copyright (C) 2022 Andreas Schneider <asn@cryptomilk.org>

+ *

+ * 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 <dlfcn.h>

+

+#include "libopenh264_dlopen.h"

+

+/*

+ * The symbol binding makes sure we do not run into strict aliasing issues which

+ * can lead into segfaults.

+ */

+typedef int (*__oh264_WelsCreateSVCEncoder)(ISVCEncoder **);

+typedef void (*__oh264_WelsDestroySVCEncoder)(ISVCEncoder *);

+typedef int (*__oh264_WelsGetDecoderCapability)(SDecoderCapability *);

+typedef long (*__oh264_WelsCreateDecoder)(ISVCDecoder **);

+typedef void (*__oh264_WelsDestroyDecoder)(ISVCDecoder *);

+typedef OpenH264Version (*__oh264_WelsGetCodecVersion)(void);

+typedef void (*__oh264_WelsGetCodecVersionEx)(OpenH264Version *);

+

+#define OH264_SYMBOL_ENTRY(i)                                                  \

+  union {                                                                      \

+    __oh264_##i f;                                                             \

+    void *obj;                                                                 \

+  } _oh264_##i

+

+struct oh264_symbols {

+  OH264_SYMBOL_ENTRY(WelsCreateSVCEncoder);

+  OH264_SYMBOL_ENTRY(WelsDestroySVCEncoder);

+  OH264_SYMBOL_ENTRY(WelsGetDecoderCapability);

+  OH264_SYMBOL_ENTRY(WelsCreateDecoder);

+  OH264_SYMBOL_ENTRY(WelsDestroyDecoder);

+  OH264_SYMBOL_ENTRY(WelsGetCodecVersion);

+  OH264_SYMBOL_ENTRY(WelsGetCodecVersionEx);

+};

+

+/* Symbols are bound by loadLibOpenH264() */

+static struct oh264_symbols openh264_symbols;

+

+int oh264_WelsCreateSVCEncoder(ISVCEncoder **ppEncoder) {

+  return openh264_symbols._oh264_WelsCreateSVCEncoder.f(ppEncoder);

+}

+

+void oh264_WelsDestroySVCEncoder(ISVCEncoder *pEncoder) {

+  return openh264_symbols._oh264_WelsDestroySVCEncoder.f(pEncoder);

+}

+

+int oh264_WelsGetDecoderCapability(SDecoderCapability *pDecCapability) {

+  return openh264_symbols._oh264_WelsGetDecoderCapability.f(pDecCapability);

+}

+

+long oh264_WelsCreateDecoder(ISVCDecoder **ppDecoder) {

+  return openh264_symbols._oh264_WelsCreateDecoder.f(ppDecoder);

+}

+

+void oh264_WelsDestroyDecoder(ISVCDecoder *pDecoder) {

+  return openh264_symbols._oh264_WelsDestroyDecoder.f(pDecoder);

+}

+

+OpenH264Version oh264_WelsGetCodecVersion(void) {

+  return openh264_symbols._oh264_WelsGetCodecVersion.f();

+}

+

+void oh264_WelsGetCodecVersionEx(OpenH264Version *pVersion) {

+  openh264_symbols._oh264_WelsGetCodecVersionEx.f(pVersion);

+}

+

+static void *_oh264_bind_symbol(AVCodecContext *avctx,

+                                void *handle,

+                                const char *sym_name) {

+    void *sym = NULL;

+

+    sym = dlsym(handle, sym_name);

+    if (sym == NULL) {

+        const char *err = dlerror();

+        av_log(avctx,

+               AV_LOG_WARNING,

+               "%s: Failed to bind %s\n",

+               err,

+               sym_name);

+        return NULL;

+    }

+

+    return sym;

+}

+

+#define oh264_bind_symbol(avctx, handle, sym_name)                           \

+  if (openh264_symbols._oh264_##sym_name.obj == NULL) {                      \

+    openh264_symbols._oh264_##sym_name.obj = _oh264_bind_symbol(avctx, handle, #sym_name); \

+    if (openh264_symbols._oh264_##sym_name.obj == NULL) {                    \

+      return 1;                                                              \

+    }                                                                        \

+  }

+

+int loadLibOpenH264(AVCodecContext *avctx) {

+  static bool initialized = false;

+  void *libopenh264 = NULL;

+  const char *err = NULL;

+

+  if (initialized) {

+      return 0;

+  }

+

+#define OPENH264_LIB "libopenh264.so.7"

+  libopenh264 = dlopen(OPENH264_LIB, RTLD_LAZY);

+  err = dlerror();

+  if (err != NULL) {

+    av_log(avctx, AV_LOG_WARNING,

+           "%s: %s is missing, openh264 support will be disabled\n", err,

+           OPENH264_LIB);

+

+    if (libopenh264 != NULL) {

+      dlclose(libopenh264);

+    }

+    return 1;

+  }

+

+  oh264_bind_symbol(avctx, libopenh264, WelsCreateSVCEncoder);

+  oh264_bind_symbol(avctx, libopenh264, WelsDestroySVCEncoder);

+  oh264_bind_symbol(avctx, libopenh264, WelsGetDecoderCapability);

+  oh264_bind_symbol(avctx, libopenh264, WelsCreateDecoder);

+  oh264_bind_symbol(avctx, libopenh264, WelsDestroyDecoder);

+  oh264_bind_symbol(avctx, libopenh264, WelsGetCodecVersion);

+  oh264_bind_symbol(avctx, libopenh264, WelsGetCodecVersionEx);

+

+  initialized = true;

+

+  return 0;

+}

Index: ffmpeg-7.1/libavcodec/libopenh264_dlopen.h

===================================================================

--- /dev/null

+++ ffmpeg-7.1/libavcodec/libopenh264_dlopen.h

@@ -0,0 +1,58 @@

+/*

+ * OpenH264 dlopen code

+ *

+ * Copyright (C) 2022 Andreas Schneider <asn@cryptomilk.org>

+ *

+ * 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 HAVE_LIBOPENH264_DLOPEN_H

+#define HAVE_LIBOPENH264_DLOPEN_H

+

+#ifdef CONFIG_LIBOPENH264_DLOPEN

+

+#include <wels/codec_api.h>

+#include <wels/codec_ver.h>

+

+#include "avcodec.h"

+

+int oh264_WelsCreateSVCEncoder(ISVCEncoder **ppEncoder);

+#define WelsCreateSVCEncoder oh264_WelsCreateSVCEncoder

+

+void oh264_WelsDestroySVCEncoder(ISVCEncoder *pEncoder);

+#define WelsDestroySVCEncoder oh264_WelsDestroySVCEncoder

+

+int oh264_WelsGetDecoderCapability(SDecoderCapability *pDecCapability);

+#define WelsGetDecoderCapability oh264_WelsGetDecoderCapability

+

+long oh264_WelsCreateDecoder(ISVCDecoder **ppDecoder);

+#define WelsCreateDecoder oh264_WelsCreateDecoder

+

+void oh264_WelsDestroyDecoder(ISVCDecoder *pDecoder);

+#define WelsDestroyDecoder oh264_WelsDestroyDecoder

+

+OpenH264Version oh264_WelsGetCodecVersion(void);

+#define WelsGetCodecVersion oh264_WelsGetCodecVersion

+

+void oh264_WelsGetCodecVersionEx(OpenH264Version *pVersion);

+#define WelsGetCodecVersionEx oh264_WelsGetCodecVersionEx

+

+int loadLibOpenH264(AVCodecContext *avctx);

+

+#endif /* CONFIG_LIBOPENH264_DLOPEN */

+

+#endif /* HAVE_LIBOPENH264_DLOPEN_H */

Index: ffmpeg-7.1/libavcodec/libopenh264dec.c

===================================================================

--- ffmpeg-7.1.orig/libavcodec/libopenh264dec.c

+++ ffmpeg-7.1/libavcodec/libopenh264dec.c

@@ -19,8 +19,12 @@

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */

+#ifdef CONFIG_LIBOPENH264_DLOPEN

+#include "libopenh264_dlopen.h"

+#else

 #include <wels/codec_api.h>

 #include <wels/codec_ver.h>

+#endif

 #include "libavutil/common.h"

 #include "libavutil/fifo.h"

@@ -55,6 +59,10 @@ static av_cold int svc_decode_init(AVCod

     int log_level;

     WelsTraceCallback callback_function;

+#ifdef CONFIG_LIBOPENH264_DLOPEN

+    if (loadLibOpenH264(avctx))

+         return AVERROR_DECODER_NOT_FOUND;

+#endif

     if (WelsCreateDecoder(&s->decoder)) {

         av_log(avctx, AV_LOG_ERROR, "Unable to create decoder\n");

         return AVERROR_UNKNOWN;

Index: ffmpeg-7.1/libavcodec/libopenh264enc.c

===================================================================

--- ffmpeg-7.1.orig/libavcodec/libopenh264enc.c

+++ ffmpeg-7.1/libavcodec/libopenh264enc.c

@@ -19,8 +19,12 @@

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */

+#ifdef CONFIG_LIBOPENH264_DLOPEN

+#include "libopenh264_dlopen.h"

+#else

 #include <wels/codec_api.h>

 #include <wels/codec_ver.h>

+#endif

 #include "libavutil/attributes.h"

 #include "libavutil/common.h"

@@ -114,6 +118,10 @@ static av_cold int svc_encode_init(AVCod

     WelsTraceCallback callback_function;

     AVCPBProperties *props;

+#ifdef CONFIG_LIBOPENH264_DLOPEN

+    if (loadLibOpenH264(avctx))

+         return AVERROR_ENCODER_NOT_FOUND;

+#endif

     if (WelsCreateSVCEncoder(&s->encoder)) {

         av_log(avctx, AV_LOG_ERROR, "Unable to create encoder\n");

         return AVERROR_UNKNOWN;

​