feat: build the MPEG-4 Visual reference decoder (vm_dec)

.gitignore

@@ -15,6 +15,7 @@ subprojects/jm/
 subprojects/libtsp-v7r0
 subprojects/mpeg2aac
 subprojects/mpeg2video
+subprojects/mpeg4video
 subprojects/vvcsoftware_vtm/
 subprojects/vvdec/
 

README.md

@@ -130,7 +130,7 @@ For complete setup, usage examples, hardware acceleration configuration, and tro
    - `./fluster.py download` downloads all available test suites
 
 2. (Optional) Build the reference decoders for AAC, H.264/AVC, H.265/HEVC,
-   H.266/VVC. First, download the ISO reference software:
+   H.266/VVC, MPEG-4 Visual. First, download the ISO reference software:
 
    ```bash
    python3 build/download_deps.py

build/compat/mpeg4video/compat.h

@@ -0,0 +1,56 @@
+/*
+ * Fluster - testing framework for decoders conformance
+ * Copyright (C) 2026, Fluendo, S.A.
+ *
+ * Force-included (-include) when building the MPEG-4 Visual reference software (vm_dec):
+ * its pre-standard C++ uses iostream names without the std:: prefix.
+ */
+
+#include <algorithm>
+#include <cmath>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <fstream>
+#include <iomanip>
+#include <iostream>
+#include <istream>
+#include <ostream>
+#include <string>
+#include <strstream>
+
+class CVideoObjectDecoder;
+class CVideoObjectDecoderTPS;
+class CEnhcBufferEncoder;
+
+using std::cerr;
+using std::cin;
+using std::cout;
+using std::dec;
+using std::endl;
+using std::ends;
+using std::fixed;
+using std::flush;
+using std::fstream;
+using std::hex;
+using std::ifstream;
+using std::ios;
+using std::iostream;
+using std::istream;
+using std::istrstream;
+using std::left;
+using std::ofstream;
+using std::oct;
+using std::ostream;
+using std::ostrstream;
+using std::right;
+using std::scientific;
+using std::setfill;
+using std::setprecision;
+using std::setw;
+using std::streambuf;
+using std::streamoff;
+using std::streampos;
+using std::strstream;
+using std::strstreambuf;
+using std::ws;

build/compat/mpeg4video/fstream.h

@@ -0,0 +1,2 @@
+/* Fluster: replacement for the pre-standard <fstream.h> used by the MPEG-4 Visual reference software */
+#include <fstream>

build/compat/mpeg4video/iomanip.h

@@ -0,0 +1,2 @@
+/* Fluster: replacement for the pre-standard <iomanip.h> used by the MPEG-4 Visual reference software */
+#include <iomanip>

build/compat/mpeg4video/ios.h

@@ -0,0 +1,2 @@
+/* Fluster: replacement for the pre-standard <ios.h> used by the MPEG-4 Visual reference software */
+#include <ios>

build/compat/mpeg4video/iostream.h

@@ -0,0 +1,2 @@
+/* Fluster: replacement for the pre-standard <iostream.h> used by the MPEG-4 Visual reference software */
+#include <iostream>

build/compat/mpeg4video/istream.h

@@ -0,0 +1,2 @@
+/* Fluster: replacement for the pre-standard <istream.h> used by the MPEG-4 Visual reference software */
+#include <istream>

build/compat/mpeg4video/ostream.h

@@ -0,0 +1,2 @@
+/* Fluster: replacement for the pre-standard <ostream.h> used by the MPEG-4 Visual reference software */
+#include <ostream>

build/compat/mpeg4video/strstream.h

@@ -0,0 +1,2 @@
+/* Fluster: replacement for the pre-standard <strstream.h> used by the MPEG-4 Visual reference software */
+#include <strstream>

build/download_deps.py

@@ -3,7 +3,7 @@
 # Copyright (C) 2025, Fluendo, S.A.
 #
 # Helper script to download all ISO reference decoder dependencies
-# Downloads: MPEG-2 AAC, MPEG-2 video, MPEG-4 AAC, and libtsp
+# Downloads: MPEG-2 AAC, MPEG-2 video, MPEG-4 AAC, MPEG-H, MPEG-4 Visual, and libtsp
 
 import argparse
 import hashlib
@@ -172,6 +172,77 @@ def download_mpegh(contrib_dir):
     spatial_decoder.write_text(re.sub(r"^[ \t]*#pragma (end)?region.*\n", "", source, flags=re.M), encoding="utf-8")
 
 
+# Forward declarations that would clash with the std:: names brought in by the compat header
+MPEG4_VIDEO_FORWARD_DECLARATION = re.compile(
+    rb"^[ \t]*class[ \t]+(istream|ostream|ifstream|strstreambuf)[ \t]*;[ \t]*\r?\n", re.M
+)
+# "ios::bin" is the pre-standard spelling of "ios::binary"
+MPEG4_VIDEO_IOS_BIN = re.compile(rb"\bios::bin\b")
+
+
+def adapt_mpeg4_video_sources(source_dir):
+    """Adapt the MPEG-4 Visual reference software, which predates C++98, to build with current compilers"""
+    for path in source_dir.rglob("*"):
+        if not path.is_file() or path.suffix not in (".c", ".cpp", ".h", ".hpp"):
+            continue
+        original = path.read_bytes()
+        adapted = MPEG4_VIDEO_IOS_BIN.sub(b"ios::binary", MPEG4_VIDEO_FORWARD_DECLARATION.sub(b"", original))
+        if adapted != original:
+            path.write_bytes(adapted)
+
+
+def download_mpeg4_video(contrib_dir):
+    """Download the MPEG-4 Visual (ISO/IEC 14496-5) reference software, which builds vm_dec"""
+    print()
+    print("=== Downloading MPEG-4 Visual reference software ===")
+
+    mpeg4_video_dir = contrib_dir / "MPEG-4_video_refSoft"
+    mpeg4_video_zip = contrib_dir / "mpeg4_video_refsoft.zip"
+    mpeg4_video_url = (
+        "https://standards.iso.org/ittf/PubliclyAvailableStandards/"
+        "c039392_ISO_IEC_14496-5_2001_Amd%205_2004(E)_Reference_Software.zip"
+    )
+    # The zip holds several implementations, only this one produces vm_dec
+    implementation = "microsoft-v2.5-040207-NTU/"
+
+    if mpeg4_video_dir.exists():
+        print(f"Skipping download of MPEG-4 Visual: {mpeg4_video_dir} already exists")
+        # Re-apply the source rewrites, in case the tree was extracted before they were added
+        adapt_mpeg4_video_sources(mpeg4_video_dir)
+        return
+
+    # Get cookies first, then download with cookies and form data
+    cookie_jar = CookieJar()
+    build_opener(HTTPCookieProcessor(cookie_jar)).open(mpeg4_video_url)
+    download_with_cookies(mpeg4_video_url, mpeg4_video_zip, cookie_jar)
+    if not zipfile.is_zipfile(mpeg4_video_zip):
+        print(f"Error: {mpeg4_video_zip.name} is not a zip file, the download was probably refused")
+        sys.exit(1)
+
+    print(f"Extracting {implementation} from {mpeg4_video_zip.name}...")
+    # Extract into a temporary directory renamed once complete, so that an interrupted run
+    # never leaves a partial MPEG-4_video_refSoft behind
+    tmp_dir = contrib_dir / f".{mpeg4_video_dir.name}.tmp"
+    shutil.rmtree(tmp_dir, ignore_errors=True)
+    with zipfile.ZipFile(mpeg4_video_zip) as zip_ref:
+        for member in zip_ref.infolist():
+            _, found, relative_path = member.filename.partition(implementation)
+            if not found or not relative_path or ".." in Path(relative_path).parts:
+                continue
+            target = tmp_dir / relative_path
+            if member.is_dir():
+                target.mkdir(parents=True, exist_ok=True)
+            else:
+                target.parent.mkdir(parents=True, exist_ok=True)
+                target.write_bytes(zip_ref.read(member))
+    mpeg4_video_zip.unlink()
+    if not tmp_dir.exists():
+        print(f"Error: {implementation} not found in the downloaded MPEG-4 Visual reference software")
+        sys.exit(1)
+    adapt_mpeg4_video_sources(tmp_dir)
+    tmp_dir.rename(mpeg4_video_dir)
+
+
 def download_libtsp(contrib_dir):
     """Download libtsp audio library"""
     print()
@@ -269,7 +340,8 @@ def prompt_iso_license(auto_accept=False):
 
 def main():
     parser = argparse.ArgumentParser(
-        description="Download ISO reference decoder dependencies (MPEG-2 AAC, MPEG-2 video, MPEG-4 AAC, MPEG-H, libtsp)"
+        description="Download ISO reference decoder dependencies "
+        "(MPEG-2 AAC, MPEG-2 video, MPEG-4 AAC, MPEG-H, MPEG-4 Visual, libtsp)"
     )
     parser.add_argument(
         "dest_dir",
@@ -300,6 +372,7 @@ def main():
     print("  - MPEG-2 video decoder")
     print("  - MPEG-4 AAC decoders")
     print("  - MPEG-H 3D Audio decoder")
+    print("  - MPEG-4 Visual decoder")
     print("  - libtsp audio library")
     print()
 
@@ -314,6 +387,7 @@ def main():
     download_mpeg2(contrib_dir)
     download_mpeg4(contrib_dir)
     download_mpegh(contrib_dir)
+    download_mpeg4_video(contrib_dir)
     download_libtsp(contrib_dir)
 
     # Copy meson.build files to contrib directories
@@ -335,13 +409,17 @@ def main():
     print("Copying meson.build for libtsp")
     shutil.copy2(packagefiles_dir / "libtsp" / "meson.build", contrib_dir / "libtsp-v7r0" / "meson.build")
 
+    print("Copying meson.build for MPEG-4 Visual")
+    shutil.copy2(packagefiles_dir / "mpeg4video" / "meson.build", contrib_dir / "MPEG-4_video_refSoft" / "meson.build")
+
     # Create symlinks for meson subprojects
     print()
     print("=== Creating symlinks for meson subprojects ===")
 
     symlinks = [
         ("mpeg2video", "../contrib/video"),
         ("mpeg2aac", "../contrib/mpeg2aac"),
+        ("mpeg4video", "../contrib/MPEG-4_video_refSoft"),
         ("libtsp-v7r0", "../contrib/libtsp-v7r0"),
     ]
 

meson.build

@@ -46,6 +46,7 @@ build_mpeg4_aac = get_option('mpeg4_aac_decoder')
 build_mpeg4_aac_er = get_option('mpeg4_aac_er_decoder')
 build_mpeg2_video = get_option('mpeg2_video_decoder')
 build_mpegh = get_option('mpegh_decoder')
+build_mpeg4_video = get_option('mpeg4_video_decoder')
 
 missing_deps = []
 
@@ -73,6 +74,13 @@ if build_mpegh
   endif
 endif
 
+# Check MPEG-4 Visual dependency
+if build_mpeg4_video
+  if not fs.is_dir(contrib_dir / 'MPEG-4_video_refSoft')
+    missing_deps += ['contrib/MPEG-4_video_refSoft (MPEG-4 Visual decoder)']
+  endif
+endif
+
 # Check libtsp dependency (needed for all AAC decoders)
 if build_mpeg2_aac or build_mpeg4_aac or build_mpeg4_aac_er
   if not fs.is_dir(contrib_dir / 'libtsp-v7r0')
@@ -242,6 +250,23 @@ if build_mpeg2_aac
   endif
 endif
 
+# MPEG-4 Visual Reference Decoder (ISO/IEC 14496-5)
+mpeg4video_tgt = disabler()
+if build_mpeg4_video
+  # Check if the mpeg4video subproject directory exists (symlinked from contrib/MPEG-4_video_refSoft)
+  mpeg4video_dir = meson.current_source_dir() / 'subprojects' / 'mpeg4video'
+  if fs.is_dir(mpeg4video_dir) or fs.is_symlink(mpeg4video_dir)
+    mpeg4video_subproject = subproject('mpeg4video', required: false)
+    if mpeg4video_subproject.found()
+      mpeg4video_tgt = mpeg4video_subproject.get_variable('vm_dec')
+    else
+      warning('MPEG-4 Visual decoder subproject configuration failed')
+    endif
+  else
+    error('MPEG-4 Visual decoder: subprojects/mpeg4video symlink not found. Run: python3 build/download_deps.py')
+  endif
+endif
+
 # Extract compiler flags from meson's C compiler configuration
 # This ensures ISO decoders use the same architecture as the main build
 c_args_list = get_option('c_args')
@@ -382,6 +407,16 @@ if not is_disabler(aacdec_mc_tgt)
   )
 endif
 
+# MPEG-4 Visual decoder symlink (vm_dec)
+if not is_disabler(mpeg4video_tgt)
+  custom_target('link-vm_dec',
+    output: 'vm_dec.link',
+    input: mpeg4video_tgt,
+    command: ['sh', '-c', link_script, '_', meson.current_build_dir(), '@INPUT@', decoders_dir / 'vm_dec'],
+    build_by_default: true,
+  )
+endif
+
 run_target('clean-contrib',
   command: ['rm', '-rf', contrib_dir],
 )
@@ -408,6 +443,7 @@ summary({
   'MPEG-2 video decoder': build_mpeg2_video,
   'MPEG-2 AAC decoder': build_mpeg2_aac,
   'MPEG-H 3D Audio decoder': build_mpegh,
+  'MPEG-4 Visual decoder': build_mpeg4_video,
   'isobmff library': build_isobmff,
 }, section: 'Meson Subproject Decoders')
 

meson_options.txt

@@ -15,6 +15,8 @@ option('mpeg4_aac_decoder', type: 'boolean', value: true,
   description: 'Build MPEG-4 AAC reference decoder')
 option('mpeg4_aac_er_decoder', type: 'boolean', value: true,
   description: 'Build MPEG-4 AAC Error Resilient reference decoder')
+option('mpeg4_video_decoder', type: 'boolean', value: true,
+  description: 'Build MPEG-4 Visual reference decoder (ISO/IEC 14496-5, vm_dec)')
 
 # MPEG-H 3D Audio reference decoder (disabled by default, needs build/download_deps.py)
 option('mpegh_decoder', type: 'boolean', value: false,

subprojects/mpeg4video.wrap

@@ -0,0 +1,6 @@
+[wrap-file]
+directory = mpeg4video
+patch_directory = mpeg4video
+
+[provide]
+program_names = vm_dec