Add new port: libtwolame - MPEG Audio Layer 2 encoder for broadcast-quality audio by Greisby · Pull Request #51728 · microsoft/vcpkg

Greisby · 2026-05-13T11:49:01Z

Description

TwoLAME is a MPEG Audio Layer 2 encoder for broadcast-quality audio.
It is an optimised encoder based on tooLAME by Mike Cheng, which itself was based on the ISO reference encoder dist10.

MP2 remains the standard audio codec for European broadcasting (DVB, DAB) and is widely used in professional media workflows.
TwoLAME is the highest-quality open-source MP2 encoder available and an encoder used by FFmpeg for MP2 output (-c:a libtwolame).

Why this port is needed

FFmpeg integration: FFmpeg's libtwolame encoder wraps this library (port must be modified later).
Building FFmpeg with --enable-libtwolame provides a broadcast-compliant MP2 encoder far superior to FFmpeg's built-in mp2 encoder.
Broadcast compliance: MP2 is mandatory in DVB (EN 300 468), DAB, and many contribution/distribution chains.
TwoLAME produces ISO 11172-3 / 13818-3 compliant bitstreams.
Quality: TwoLAME implements psychoacoustic model improvements and produces better output than the reference encoder, particularly at lower bitrates (128–192 kbps stereo) used in broadcast.

Build strategy

Platform	Build system	Notes
Windows	CMake	Custom minimal `CMakeLists.txt` (library-only build)
Linux/macOS	Autotools	Native `./configure` via `vcpkg_configure_make(AUTOCONFIG)`

Upstream ships an autotools build system only.
On Windows, a custom CMakeLists.txt is provided for MSVC compatibility (library build only — no CLI tool).

Patches

Patch	Purpose
`001-fix-tl-api-export.patch`	Fix `TWOLAME_DLL` / `dllexport` for shared builds
`002-disable-doc-subdir.patch`	Remove `doc` subdir from build; fix `pkgdoc_DATA` filenames (`README.md`, `NEWS.md`)

Additional portfile fix (no upstream source patch):

Post-install pkg-config normalization for static Linux builds to expose -lm in Libs.

Greisby · 2026-05-13T11:59:17Z

sorry, forgot to switch to master first...

dg0yt

Same buildsystem comment as in the other PR.

dg0yt · 2026-05-13T17:14:37Z

+
+    if("tool" IN_LIST FEATURES)
+        # twolame binary is installed in tools/libtwolame/bin by vcpkg_configure_make's custom bindir
+        vcpkg_copy_tools(TOOL_NAMES twolame AUTO_CLEAN SEARCH_DIR "${CURRENT_PACKAGES_DIR}/tools/libtwolame/bin")
+    endif()


Suggested change

if("tool" IN_LIST FEATURES)

# twolame binary is installed in tools/libtwolame/bin by vcpkg_configure_make's custom bindir

vcpkg_copy_tools(TOOL_NAMES twolame AUTO_CLEAN SEARCH_DIR "${CURRENT_PACKAGES_DIR}/tools/libtwolame/bin")

endif()

In general tools are not moved from tools/<port>/bin to tools/<port>.

dg0yt · 2026-05-13T17:15:59Z

+# For static builds, autotools puts -lm in Libs.Private which is only used with pkg-config --static.
+# Consumers like FFmpeg use plain --libs, so the link test fails on math symbols (pow, cos, lrintf...).
+# Move -lm into Libs.
+if(NOT VCPKG_TARGET_IS_WINDOWS AND VCPKG_LIBRARY_LINKAGE STREQUAL "static")
+    foreach(_pc_suffix IN ITEMS "lib/pkgconfig/twolame.pc" "debug/lib/pkgconfig/twolame.pc")
+        set(_pc_file "${CURRENT_PACKAGES_DIR}/${_pc_suffix}")
+        if(EXISTS "${_pc_file}")
+            file(READ "${_pc_file}" _pc_content)
+            string(REPLACE "-ltwolame" "-ltwolame -lm" _pc_content "${_pc_content}")
+            string(REGEX REPLACE "Libs\\.Private:[^\n]*" "Libs.Private:" _pc_content "${_pc_content}")
+            file(WRITE "${_pc_file}" "${_pc_content}")
+        endif()
+    endforeach()
+endif()
+


vcpkg_fixup_pkgconfig does the merging of xxx.Private into xxx.

vicroms · 2026-05-14T18:32:50Z

+option(BUILD_SHARED_LIBS "Build shared library" OFF)
+


Suggested change

option(BUILD_SHARED_LIBS "Build shared library" OFF)

Set by the vcpkg toolchain.

vicroms · 2026-05-14T18:46:42Z

+install(TARGETS twolame
+    EXPORT twolame-targets
+    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+    ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+    PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+)
+
+install(EXPORT twolame-targets
+    FILE twolameConfig.cmake
+    NAMESPACE twolame::
+    DESTINATION share/twolame
+)


Unofficial targets should be namespaced (unofficial::twolame)

Full rules covers the CMake package name, too: unofficial-<PORT>.

vicroms · 2026-05-14T18:47:25Z

+
+Name: TwoLAME
+Description: Optimised MPEG Audio Layer 2 (MP2) encoder
+Version: ${PROJECT_VERSION}


PROJECT_VERSION is not set

vicroms · 2026-05-14T18:51:31Z

+    vcpkg_cmake_build()
+    vcpkg_cmake_install()


Suggested change

vcpkg_cmake_build()

vcpkg_cmake_install()

vcpkg_cmake_install()

vcpkg_cmake_fixup_config(PACKAGE_NAME unofficial-twolame)

vicroms · 2026-05-14T18:52:33Z

+vcpkg_from_github(
+    OUT_SOURCE_PATH SOURCE_PATH
+    REPO njh/twolame
+    REF 0.4.0


Suggested change

REF 0.4.0

REF "${VERSION}"

VERSION is filled automatically and matches the version declared in vcpkg.json

vicroms · 2026-05-14T19:59:07Z

+if(VCPKG_TARGET_IS_WINDOWS)
+    # Upstream has no CMakeLists.txt suitable for library-only builds.
+    # Use our own minimal CMakeLists.txt.
+    file(COPY "${CMAKE_CURRENT_LIST_DIR}/CMakeLists.txt" DESTINATION "${SOURCE_PATH}")


Why not use vcpkg_configure_make on Windows? It should work alright but you will need to add pkgconfig to path for .pc files to work.

vcpkg_find_acquire_program(PKGCONFIG) get_filename_component(PKGCONFIG_DIR "${PKGCONFIG}" DIRECTORY) vcpkg_add_to_path("${PKGCONFIG_DIR}")

Good question.
This is also based on a port I made a few years ago.
I'll try to get it working with autotools.

vicroms · 2026-05-14T20:02:48Z

+        patches/001-fix-tl-api-export.patch
+        patches/002-disable-doc-subdir.patch
+        patches/003-fix-kr-declaration.patch


Have you submitted patches 001 and 003 upstream?

No, but they were already submitted and merged upstream:

001: https://github.com/njh/twolame/pull/97/changes (Jul 2021)

003: https://github.com/njh/twolame/pull/105/changes (Feb this year)

Since then (2021!), no new version was tagged, so I included them.

Greisby · 2026-05-15T21:56:02Z

It was pretty straightforward, BUT
for any strange reason, vcpkg_fixup_pkgconfig() does not do its job.
The installed pc (on linux, static) contains this after vcpkg_fixup_pkgconfig():

prefix=${pcfiledir}/../..
exec_prefix=${prefix}
libdir=${prefix}/lib
includedir=${prefix}/include

Name: twosome
Description: An optimized MPEG Audio Layer 2 encoder
Version: 0.4.0
Libs.Private: -lm -lm 

Libs: "-L${libdir}" -ltwolame
Requires: 
Cflags: "-I${includedir}" -DLIBTWOLAME_STATIC

The -lm was not moved from Libs.Private to Libs.
I had to re-introduce the manual patching.

Any clue?

dg0yt · 2026-05-16T06:48:25Z

The -lm was not moved from Libs.Private to Libs. I had to re-introduce the manual patching.

Any clue?

Case issue. Libs.private is the usual spelling. (Admittedly I believe that I have seen other spellings.) Not sure it spec or tools are very strict.

Greisby · 2026-05-16T19:15:40Z

This is a strange check error.
I followed the full process again:

git fetch https://github.com/microsoft/vcpkg master
git merge-base HEAD FETCH_HEAD
git restore --source=8...bb --staged --worktree -- versions
git clean -fd -- versions
vcpkg format-manifest ports/libtwolame/vcpkg.json
vcpkg x-add-version --all
git add -u & git add versions/l-/libtwolame.json
git status → no change

so my last commit was correct.

Co-authored-by: Kai Pastor <dg0yt@darc.de>

Greisby · 2026-05-18T08:41:09Z

By the way, could the “check for common mistakes” failure be caused by the branch being out of date?

dg0yt · 2026-05-18T18:37:51Z

By the way, could the “check for common mistakes” failure be caused by the branch being out of date?

These checks are usually made agains merge commits. So either it sees a fresh picture, or it doesn't start due to merge conflict.

vicroms · 2026-05-19T07:06:47Z

By the way, could the “check for common mistakes” failure be caused by the branch being out of date?

I've seen it happen when the branch is more than 50 commits out of date.

Greisby · 2026-05-19T10:09:11Z

Thanks, I hesitated to do it myself.

New port

5ddcbca

Greisby force-pushed the new-libtwolame branch from 2afd01a to 5ddcbca Compare May 13, 2026 11:58

Greisby marked this pull request as draft May 13, 2026 12:44

Greisby added 2 commits May 13, 2026 15:15

Fixed tool location

a9d58c3

forgot version file...

d815f52

dg0yt reviewed May 13, 2026

View reviewed changes

addressed reviewer feedback + fixed K&R build error on macOS

ad9d257

Greisby marked this pull request as ready for review May 14, 2026 12:16

vicroms requested changes May 14, 2026

View reviewed changes

vicroms marked this pull request as draft May 14, 2026 20:03

pure autotools

87f1403

fixed .pc

7c7b95b

dg0yt reviewed May 17, 2026

View reviewed changes

Comment thread ports/libtwolame/portfile.cmake

Greisby and others added 2 commits May 17, 2026 13:18

Update ports/libtwolame/portfile.cmake

f6d8c64

Co-authored-by: Kai Pastor <dg0yt@darc.de>

updated version

3eafa09

Merge branch 'master' into new-libtwolame

0f3f5b4

Greisby marked this pull request as ready for review May 19, 2026 10:09

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Greisby commented May 13, 2026

Description

Why this port is needed

Build strategy

Patches

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Greisby commented May 13, 2026

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Greisby May 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Greisby commented May 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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dg0yt commented May 16, 2026

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Greisby commented May 18, 2026

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dg0yt commented May 18, 2026

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vicroms commented May 19, 2026

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Greisby May 14, 2026 •

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