examples : add support for decoding input with ffmpeg (Linux) (#2133)

- search for ffmpeg libs/headers at cmake time
- added ffmpeg-transcode.cpp into libcommon if ffmpeg on
- hooked ffmpeg trancoding in common read_wav(...)
- passed test:
./main -m ggml-base.en.bin -f samples/jfk.mp3

CMakeLists.txt

@@ -59,6 +59,10 @@ option(WHISPER_BUILD_EXAMPLES         "whisper: build examples" ${WHISPER_STANDA
 
 option(WHISPER_SDL2                   "whisper: support for libSDL2" OFF)
 
+if (CMAKE_SYSTEM_NAME MATCHES "Linux")
+    option(WHISPER_FFMPEG                 "whisper: support building and linking with ffmpeg libs (avcodec, swresample, ...)" OFF)
+endif()
+
 option(WHISPER_NO_AVX                 "whisper: disable AVX"         OFF)
 option(WHISPER_NO_AVX2                "whisper: disable AVX2"        OFF)
 option(WHISPER_NO_AVX512              "whisper: disable AVX512"      ON)
@@ -125,6 +129,26 @@ else()
     set(CMAKE_CXX_STANDARD 11)
 endif()
 
+if (WHISPER_FFMPEG)
+    # As of cmake 3.27, there is no official cmake support for FindFFmpeg.
+    # Consequnelty we added a FindFFmpeg.cmake script the cmake subfolder:
+    # whisper.cpp does not need the full ffmpeg libs, just AVFORMAT AVCODEC AVUTIL SWRESAMPLE
+    # libswresample  performs highly optimized audio resampling, rematrixing and sample format conversion operations
+    # libavcodec provides a generic encoding/decoding framework and contains multiple decoders and encoders for audio, video and subtitle streams, and several bitstream filters.
+    # libavformat provides a generic framework for multiplexing and demultiplexing (muxing and demuxing) audio, video and subtitle streams.
+    find_package(FFmpeg REQUIRED)
+    if (NOT ${FFMPEG_FOUND})
+        message(FATAL_ERROR "Cannot find ffmpeg libs/headers")
+    endif()
+    message(STATUS "Found ffmpeg libs: ${FFMPEG_LIBRARIES}")
+    message(STATUS "Found ffmpeg headers in: ${FFMPEG_INCLUDE_DIRS}")
+    message(STATUS "ffmpeg definitions: ${FFMPEG_DEFINITIONS}")
+    message(STATUS "Found avformat ${AVFORMAT_VERSION}")
+    include_directories(${FFMPEG_INCLUDE_DIRS})
+    add_compile_definitions(WHISPER_FFMPEG)
+    set(WHISPER_EXTRA_LIBS  ${WHISPER_EXTRA_LIBS} ${FFMPEG_LIBRARIES})
+endif()
+
 # on APPLE
 if (APPLE)
     # include Accelerate framework

cmake/FindFFmpeg.cmake

@@ -0,0 +1,163 @@
+# From
+# https://github.com/snikulov/cmake-modules/blob/master/FindFFmpeg.cmake
+#
+# vim: ts=2 sw=2
+# - Try to find the required ffmpeg components(default: AVFORMAT, AVUTIL, AVCODEC)
+#
+# Once done this will define
+#  FFMPEG_FOUND         - System has the all required components.
+#  FFMPEG_INCLUDE_DIRS  - Include directory necessary for using the required components headers.
+#  FFMPEG_LIBRARIES     - Link these to use the required ffmpeg components.
+#  FFMPEG_DEFINITIONS   - Compiler switches required for using the required ffmpeg components.
+#
+# For each of the components it will additionally set.
+#   - AVCODEC
+#   - AVDEVICE
+#   - AVFORMAT
+#   - AVFILTER
+#   - AVUTIL
+#   - POSTPROC
+#   - SWSCALE
+# the following variables will be defined
+#  <component>_FOUND        - System has <component>
+#  <component>_INCLUDE_DIRS - Include directory necessary for using the <component> headers
+#  <component>_LIBRARIES    - Link these to use <component>
+#  <component>_DEFINITIONS  - Compiler switches required for using <component>
+#  <component>_VERSION      - The components version
+#
+# Copyright (c) 2006, Matthias Kretz, <kretz@kde.org>
+# Copyright (c) 2008, Alexander Neundorf, <neundorf@kde.org>
+# Copyright (c) 2011, Michael Jansen, <kde@michael-jansen.biz>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+
+include(FindPackageHandleStandardArgs)
+
+# The default components were taken from a survey over other FindFFMPEG.cmake files
+if (NOT FFmpeg_FIND_COMPONENTS)
+  set(FFmpeg_FIND_COMPONENTS AVFORMAT AVCODEC AVUTIL SWRESAMPLE) 
+endif()
+
+#
+### Macro: set_component_found
+#
+# Marks the given component as found if both *_LIBRARIES AND *_INCLUDE_DIRS is present.
+#
+macro(set_component_found _component )
+  if (${_component}_LIBRARIES AND ${_component}_INCLUDE_DIRS)
+    message(DEBUG "  - ${_component} found.")
+    set(${_component}_FOUND TRUE)
+  else ()
+  message(DEBUG "  - ${_component} not found.")
+  endif ()
+endmacro()
+
+#
+### Macro: find_component
+#
+# Checks for the given component by invoking pkgconfig and then looking up the libraries and
+# include directories.
+#
+macro(find_component _component _pkgconfig _library _header)
+
+  if (NOT WIN32)
+     # use pkg-config to get the directories and then use these values
+     # in the FIND_PATH() and FIND_LIBRARY() calls
+     find_package(PkgConfig)
+     if (PKG_CONFIG_FOUND)
+       pkg_check_modules(PC_${_component} ${_pkgconfig})
+       message(STATUS "Pkgconfig found: ${PC_${_component}_INCLUDEDIR}")
+       message(STATUS "Pkgconfig found: ${PC_${_component}_INCLUDE_DIRS}")
+       message(STATUS "${PC_${_component}_CFLAGS}")
+     endif ()
+  endif (NOT WIN32)
+
+
+  find_path(${_component}_INCLUDE_DIRS ${_header}
+    HINTS
+      ${PC_${_component}_INCLUDEDIR}
+      ${PC_${_component}_INCLUDE_DIRS}
+    PATH_SUFFIXES
+      ffmpeg
+  )
+
+  # CMake's default is to search first for shared libraries and then for static libraries.
+  # Todo later: add option to prefer static libs over dynamic:
+  find_library(${_component}_LIBRARIES NAMES ${_library} lib${_library}.a  
+      HINTS
+      ${PC_${_component}_LIBDIR}
+      ${PC_${_component}_LIBRARY_DIRS}
+  )
+
+  set(${_component}_DEFINITIONS  ${PC_${_component}_CFLAGS_OTHER} CACHE STRING "The ${_component} CFLAGS.")
+  set(${_component}_VERSION      ${PC_${_component}_VERSION}      CACHE STRING "The ${_component} version number.")
+
+  set_component_found(${_component})
+
+  mark_as_advanced(
+    ${_component}_INCLUDE_DIRS
+    ${_component}_LIBRARIES
+    ${_component}_DEFINITIONS
+    ${_component}_VERSION)
+
+endmacro()
+
+
+# Check for cached results. If there are skip the costly part.
+if (NOT FFMPEG_LIBRARIES)
+
+  # Check for all possible component.
+  find_component(AVCODEC    libavcodec    avcodec  libavcodec/avcodec.h)
+  find_component(AVFORMAT   libavformat   avformat libavformat/avformat.h)
+  find_component(AVDEVICE   libavdevice   avdevice libavdevice/avdevice.h)
+  #find_component(AVRESAMPLE libavresample avresample libavresample/avresample.h) # old name for swresample
+  find_component(AVUTIL     libavutil     avutil   libavutil/avutil.h)
+  find_component(AVFILTER   libavfilter   avfilter libavfilter/avfilter.h)
+  find_component(SWSCALE    libswscale    swscale  libswscale/swscale.h)
+  find_component(POSTPROC   libpostproc   postproc libpostproc/postprocess.h)
+  find_component(SWRESAMPLE libswresample swresample libswresample/swresample.h)
+
+  # Check if the required components were found and add their stuff to the FFMPEG_* vars.
+  foreach (_component ${FFmpeg_FIND_COMPONENTS})
+    if (${_component}_FOUND)
+      # message(STATUS "Required component ${_component} present.")
+      set(FFMPEG_LIBRARIES   ${FFMPEG_LIBRARIES}   ${${_component}_LIBRARIES})
+      set(FFMPEG_DEFINITIONS ${FFMPEG_DEFINITIONS} ${${_component}_DEFINITIONS})
+      list(APPEND FFMPEG_INCLUDE_DIRS ${${_component}_INCLUDE_DIRS})
+    else ()
+      # message(STATUS "Required component ${_component} missing.")
+    endif ()
+  endforeach ()
+
+  # Build the include path with duplicates removed.
+  if (FFMPEG_INCLUDE_DIRS)
+    list(REMOVE_DUPLICATES FFMPEG_INCLUDE_DIRS)
+  endif ()
+
+  # cache the vars.
+  set(FFMPEG_INCLUDE_DIRS ${FFMPEG_INCLUDE_DIRS} CACHE STRING "The FFmpeg include directories." FORCE)
+  set(FFMPEG_LIBRARIES    ${FFMPEG_LIBRARIES}    CACHE STRING "The FFmpeg libraries." FORCE)
+  set(FFMPEG_DEFINITIONS  ${FFMPEG_DEFINITIONS}  CACHE STRING "The FFmpeg cflags." FORCE)
+
+  mark_as_advanced(FFMPEG_INCLUDE_DIRS
+                   FFMPEG_LIBRARIES
+                   FFMPEG_DEFINITIONS)
+
+endif ()
+
+# Now set the noncached _FOUND vars for the components.
+# whisper.cpp does not need SWSCALE
+foreach (_component AVCODEC AVDEVICE AVFORMAT AVRESAMPLE AVUTIL POSTPROCESS)
+  set_component_found(${_component})
+endforeach ()
+
+# Compile the list of required vars
+set(_FFmpeg_REQUIRED_VARS FFMPEG_LIBRARIES FFMPEG_INCLUDE_DIRS)
+foreach (_component ${FFmpeg_FIND_COMPONENTS})
+  list(APPEND _FFmpeg_REQUIRED_VARS ${_component}_LIBRARIES ${_component}_INCLUDE_DIRS)
+endforeach ()
+
+# Give a nice error message if some of the required vars are missing.
+find_package_handle_standard_args(FFmpeg DEFAULT_MSG ${_FFmpeg_REQUIRED_VARS})
+

examples/CMakeLists.txt

@@ -22,6 +22,10 @@ endif()
 
 set(TARGET common)
 
+if (WHISPER_FFMPEG)
+    set(COMMON_SOURCES_FFMPEG ffmpeg-transcode.cpp)
+endif()
+
 add_library(${TARGET} STATIC
     common.h
     common.cpp
@@ -29,6 +33,7 @@ add_library(${TARGET} STATIC
     common-ggml.cpp
     grammar-parser.h
     grammar-parser.cpp
+    ${COMMON_SOURCES_FFMPEG}
     )
 
 include(DefaultTargetOptions)

examples/common.cpp

@@ -24,6 +24,11 @@
 #include <io.h>
 #endif
 
+#ifdef WHISPER_FFMPEG
+// as implemented in ffmpeg_trancode.cpp only embedded in common lib if whisper built with ffmpeg support
+extern bool ffmpeg_decode_audio(const std::string & ifname, std::vector<uint8_t> & wav_data);
+#endif
+
 // Function to check if the next argument exists
 std::string get_next_arg(int& i, int argc, char** argv, const std::string& flag, gpt_params& params) {
     if (i + 1 < argc && argv[i + 1][0] != '-') {
@@ -637,7 +642,7 @@ bool is_wav_buffer(const std::string buf) {
 
 bool read_wav(const std::string & fname, std::vector<float>& pcmf32, std::vector<std::vector<float>>& pcmf32s, bool stereo) {
     drwav wav;
-    std::vector<uint8_t> wav_data; // used for pipe input from stdin
+    std::vector<uint8_t> wav_data; // used for pipe input from stdin or ffmpeg decoding output
 
     if (fname == "-") {
         {
@@ -670,8 +675,19 @@ bool read_wav(const std::string & fname, std::vector<float>& pcmf32, std::vector
         }
     }
     else if (drwav_init_file(&wav, fname.c_str(), nullptr) == false) {
+#if defined(WHISPER_FFMPEG)
+        if (ffmpeg_decode_audio(fname, wav_data) != 0) {
+            fprintf(stderr, "error: failed to ffmpeg decode '%s' \n", fname.c_str());
+            return false;
+        }
+        if (drwav_init_memory(&wav, wav_data.data(), wav_data.size(), nullptr) == false) {
+            fprintf(stderr, "error: failed to read wav data as wav \n");
+            return false;
+        }
+#else
         fprintf(stderr, "error: failed to open '%s' as WAV file\n", fname.c_str());
         return false;
+#endif
     }
 
     if (wav.channels != 1 && wav.channels != 2) {

examples/ffmpeg-transcode.cpp

@@ -0,0 +1,350 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * transcode.c - convert audio file to WAVE
+ *
+ * Copyright (C) 2019		Andrew Clayton <andrew@digital-domain.net>
+ * Copyright (C) 2024       William Tambellini <william.tambellini@gmail.com>
+ */
+
+// Just for conveninent C++ API
+#include <vector>
+#include <string>
+
+// C
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+extern "C" {
+#include <libavutil/opt.h>
+#include <libavcodec/avcodec.h>
+#include <libavformat/avformat.h>
+#include <libswresample/swresample.h>
+}
+
+typedef uint64_t u64;
+typedef int64_t  s64;
+typedef uint32_t u32;
+typedef int32_t  s32;
+typedef uint16_t u16;
+typedef int16_t  s16;
+typedef uint8_t   u8;
+typedef int8_t    s8;
+
+#define WAVE_SAMPLE_RATE	16000
+#define AVIO_CTX_BUF_SZ		 4096
+
+static const char* ffmpegLog = getenv("FFMPEG_LOG");
+// Todo: add __FILE__ __LINE__
+#define LOG(...) \
+  do { if (ffmpegLog) fprintf(stderr, __VA_ARGS__); } while(0) // C99
+
+/*
+ * WAVE file header based on definition from
+ * https://gist.github.com/Jon-Schneider/8b7c53d27a7a13346a643dac9c19d34f
+ *
+ * We must ensure this structure doesn't have any holes or
+ * padding so we can just map it straight to the WAVE data.
+ */
+struct wave_hdr {
+	/* RIFF Header: "RIFF" */
+	char riff_header[4];
+	/* size of audio data + sizeof(struct wave_hdr) - 8 */
+	int wav_size;
+	/* "WAVE" */
+	char wav_header[4];
+
+	/* Format Header */
+	/* "fmt " (includes trailing space) */
+	char fmt_header[4];
+	/* Should be 16 for PCM */
+	int fmt_chunk_size;
+	/* Should be 1 for PCM. 3 for IEEE Float */
+	s16 audio_format;
+	s16 num_channels;
+	int sample_rate;
+	/*
+	 * Number of bytes per second
+	 * sample_rate * num_channels * bit_depth/8
+	 */
+	int byte_rate;
+	/* num_channels * bytes per sample */
+	s16 sample_alignment;
+	/* bits per sample */
+	s16 bit_depth;
+
+	/* Data Header */
+	/* "data" */
+	char data_header[4];
+	/*
+	 * size of audio
+	 * number of samples * num_channels * bit_depth/8
+	 */
+	int data_bytes;
+} __attribute__((__packed__));
+
+struct audio_buffer {
+	u8 *ptr;
+	int size; /* size left in the buffer */
+};
+
+static void set_wave_hdr(wave_hdr& wh, size_t size) {
+    memcpy(&wh.riff_header, "RIFF", 4);
+    wh.wav_size = size + sizeof(struct wave_hdr) - 8;
+    memcpy(&wh.wav_header, "WAVE", 4);
+    memcpy(&wh.fmt_header, "fmt ", 4);
+    wh.fmt_chunk_size = 16;
+    wh.audio_format = 1;
+    wh.num_channels = 1;
+    wh.sample_rate = WAVE_SAMPLE_RATE;
+    wh.sample_alignment = 2;
+    wh.bit_depth = 16;
+    wh.byte_rate = wh.sample_rate * wh.sample_alignment;
+    memcpy(&wh.data_header, "data", 4);
+    wh.data_bytes = size;
+}
+
+static void write_wave_hdr(int fd, size_t size) {
+	struct wave_hdr wh;
+    set_wave_hdr(wh, size);
+	write(fd, &wh, sizeof(struct wave_hdr));
+}
+
+static int map_file(int fd, u8 **ptr, size_t *size)
+{
+	struct stat sb;
+
+	fstat(fd, &sb);
+	*size = sb.st_size;
+
+    *ptr = (u8*)mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
+	if (*ptr == MAP_FAILED) {
+		perror("mmap");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int read_packet(void *opaque, u8 *buf, int buf_size)
+{
+    struct audio_buffer *audio_buf = (audio_buffer*)opaque;
+
+	buf_size = FFMIN(buf_size, audio_buf->size);
+
+	/* copy internal buffer data to buf */
+	memcpy(buf, audio_buf->ptr, buf_size);
+	audio_buf->ptr += buf_size;
+	audio_buf->size -= buf_size;
+
+	return buf_size;
+}
+
+static void convert_frame(struct SwrContext *swr, AVCodecContext *codec,
+			  AVFrame *frame, s16 **data, int *size, bool flush)
+{
+	int nr_samples;
+	s64 delay;
+	u8 *buffer;
+
+	delay = swr_get_delay(swr, codec->sample_rate);
+	nr_samples = av_rescale_rnd(delay + frame->nb_samples,
+				    WAVE_SAMPLE_RATE, codec->sample_rate,
+				    AV_ROUND_UP);
+	av_samples_alloc(&buffer, NULL, 1, nr_samples, AV_SAMPLE_FMT_S16, 0);
+
+	/*
+	 * !flush is used to check if we are flushing any remaining
+	 * conversion buffers...
+	 */
+	nr_samples = swr_convert(swr, &buffer, nr_samples,
+				 !flush ? (const u8 **)frame->data : NULL,
+				 !flush ? frame->nb_samples : 0);
+
+    *data = (s16*)realloc(*data, (*size + nr_samples) * sizeof(s16));
+	memcpy(*data + *size, buffer, nr_samples * sizeof(s16));
+	*size += nr_samples;
+	av_freep(&buffer);
+}
+
+static bool is_audio_stream(const AVStream *stream)
+{
+	if (stream->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)
+		return true;
+
+	return false;
+}
+
+// Return non zero on error, 0 on success
+// audio_buffer: input memory
+// data: decoded output audio data (wav file)
+// size: size of output data
+static int decode_audio(struct audio_buffer *audio_buf, s16 **data, int *size)
+{
+    LOG("decode_audio: input size: %d\n", audio_buf->size);
+	AVFormatContext *fmt_ctx;
+	AVIOContext *avio_ctx;
+	AVStream *stream;
+	AVCodecContext *codec;
+	AVPacket packet;
+	AVFrame *frame;
+	struct SwrContext *swr;
+	u8 *avio_ctx_buffer;
+	unsigned int i;
+	int stream_index = -1;
+	int err;
+    const size_t errbuffsize = 1024;
+    char errbuff[errbuffsize];
+
+    av_register_all(); // from avformat. Still a must-have call for ffmpeg v3! (can be skipped for later versions)
+
+    fmt_ctx = avformat_alloc_context();
+    avio_ctx_buffer = (u8*)av_malloc(AVIO_CTX_BUF_SZ);
+    LOG("Creating an avio context: AVIO_CTX_BUF_SZ=%d\n", AVIO_CTX_BUF_SZ);
+    avio_ctx = avio_alloc_context(avio_ctx_buffer, AVIO_CTX_BUF_SZ, 0, audio_buf, &read_packet, NULL, NULL);
+	fmt_ctx->pb = avio_ctx;
+
+    // open the input stream and read header
+	err = avformat_open_input(&fmt_ctx, NULL, NULL, NULL);
+	if (err) {
+        LOG("Could not read audio buffer: %d: %s\n", err, av_make_error_string(errbuff, errbuffsize, err));
+        return err;
+	}
+
+	err = avformat_find_stream_info(fmt_ctx, NULL);
+	if (err < 0) {
+        LOG("Could not retrieve stream info from audio buffer: %d\n", err);
+        return err;
+	}
+
+	for (i = 0; i < fmt_ctx->nb_streams; i++) {
+		if (is_audio_stream(fmt_ctx->streams[i])) {
+			stream_index = i;
+			break;
+		}
+	}
+
+	if (stream_index == -1) {
+        LOG("Could not retrieve audio stream from buffer\n");
+		return -1;
+	}
+
+	stream = fmt_ctx->streams[stream_index];
+	codec = avcodec_alloc_context3(
+			avcodec_find_decoder(stream->codecpar->codec_id));
+	avcodec_parameters_to_context(codec, stream->codecpar);
+	err = avcodec_open2(codec, avcodec_find_decoder(codec->codec_id),
+							NULL);
+	if (err) {
+        LOG("Failed to open decoder for stream #%d in audio buffer\n", stream_index);
+        return err;
+	}
+
+	/* prepare resampler */
+	swr = swr_alloc();
+
+	av_opt_set_int(swr, "in_channel_count", codec->channels, 0);
+	av_opt_set_int(swr, "out_channel_count", 1, 0);
+	av_opt_set_int(swr, "in_channel_layout", codec->channel_layout, 0);
+	av_opt_set_int(swr, "out_channel_layout", AV_CH_LAYOUT_MONO, 0);
+	av_opt_set_int(swr, "in_sample_rate", codec->sample_rate, 0);
+	av_opt_set_int(swr, "out_sample_rate", WAVE_SAMPLE_RATE, 0);
+	av_opt_set_sample_fmt(swr, "in_sample_fmt", codec->sample_fmt, 0);
+	av_opt_set_sample_fmt(swr, "out_sample_fmt", AV_SAMPLE_FMT_S16, 0);
+
+	swr_init(swr);
+	if (!swr_is_initialized(swr)) {
+        LOG("Resampler has not been properly initialized\n");
+		return -1;
+	}
+
+	av_init_packet(&packet);
+	frame = av_frame_alloc();
+	if (!frame) {
+        LOG("Error allocating the frame\n");
+		return -1;
+	}
+
+	/* iterate through frames */
+	*data = NULL;
+	*size = 0;
+	while (av_read_frame(fmt_ctx, &packet) >= 0) {
+		avcodec_send_packet(codec, &packet);
+
+		err = avcodec_receive_frame(codec, frame);
+		if (err == AVERROR(EAGAIN))
+			continue;
+
+		convert_frame(swr, codec, frame, data, size, false);
+	}
+	/* Flush any remaining conversion buffers... */
+	convert_frame(swr, codec, frame, data, size, true);
+
+	av_frame_free(&frame);
+	swr_free(&swr);
+    //avio_context_free(); // todo?
+	avcodec_close(codec);
+	avformat_close_input(&fmt_ctx);
+	avformat_free_context(fmt_ctx);
+
+	if (avio_ctx) {
+		av_freep(&avio_ctx->buffer);
+		av_freep(&avio_ctx);
+	}
+
+	return 0;
+}
+
+// in mem decoding/conversion/resampling:
+// ifname: input file path
+// owav_data: in mem wav file. Can be forwarded as it to whisper/drwav
+// return 0 on success
+int ffmpeg_decode_audio(const std::string &ifname, std::vector<uint8_t>& owav_data) {
+    LOG("ffmpeg_decode_audio: %s\n", ifname.c_str());
+    int ifd = open(ifname.c_str(), O_RDONLY);
+    if (ifd == -1) {
+        fprintf(stderr, "Couldn't open input file %s\n", ifname.c_str());
+        return -1;
+    }
+    u8 *ibuf = NULL;
+    size_t ibuf_size;
+    int err = map_file(ifd, &ibuf, &ibuf_size);
+    if (err) {
+        LOG("Couldn't map input file %s\n", ifname.c_str());
+        return err;
+    }
+    LOG("Mapped input file: %x size: %d\n", ibuf, ibuf_size);
+    struct audio_buffer inaudio_buf;
+    inaudio_buf.ptr = ibuf;
+    inaudio_buf.size = ibuf_size;
+
+    s16 *odata=NULL;
+    int osize=0;
+
+    err = decode_audio(&inaudio_buf, &odata, &osize);
+    LOG("decode_audio returned %d \n", err);
+    if (err != 0) {
+        LOG("decode_audio failed\n");
+        return err;
+    }
+    LOG("decode_audio output size: %d\n", osize);
+
+    wave_hdr wh;
+    const size_t outdatasize = osize * sizeof(s16);
+    set_wave_hdr(wh, outdatasize);
+    owav_data.resize(sizeof(wave_hdr) + outdatasize);
+    // header:
+    memcpy(owav_data.data(), &wh, sizeof(wave_hdr));
+    // the data:
+    memcpy(owav_data.data() + sizeof(wave_hdr), odata, osize* sizeof(s16));
+
+    return 0;
+}

examples/main/CMakeLists.txt

@@ -3,4 +3,4 @@ add_executable(${TARGET} main.cpp)
 
 include(DefaultTargetOptions)
 
-target_link_libraries(${TARGET} PRIVATE common whisper ${CMAKE_THREAD_LIBS_INIT})
+target_link_libraries(${TARGET} PRIVATE common whisper ${FFMPEG_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})

samples/.gitignore

@@ -1 +1,4 @@
 *
+!jfk.wave
+!jfk.mp3
+

tests/CMakeLists.txt

@@ -74,3 +74,14 @@ add_test(NAME ${TEST_TARGET}
     -m ${PROJECT_SOURCE_DIR}/models/for-tests-ggml-large.bin
     -f ${PROJECT_SOURCE_DIR}/samples/jfk.wav)
 set_tests_properties(${TEST_TARGET} PROPERTIES LABELS "large")
+
+if (WHISPER_FFMPEG)
+    set(TEST_TARGET test-main-tiny-mp3)
+    # Check with reviewers: any way to check the output transcription via ctest (diff, ...)?
+    add_test(NAME ${TEST_TARGET}
+      COMMAND $<TARGET_FILE:main>
+      -m ${PROJECT_SOURCE_DIR}/models/for-tests-ggml-tiny.en.bin
+      -f ${PROJECT_SOURCE_DIR}/samples/jfk.mp3)
+    set_tests_properties(${TEST_TARGET} PROPERTIES LABELS "tiny;mp3")
+endif()
+