Utilities: Add aconv for converting between audio formats

The intention for this utility is to eventually become a general-purpose
multimedia conversion tool like ffmpeg (except probably not with as many
supported formats, stream mappings and filters). For now, we can not
write any video format so the added complexity is not necessary at the
moment.

Userland/Utilities/aconv.cpp

@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2023, kleines Filmröllchen <filmroellchen@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/LexicalPath.h>
+#include <AK/Types.h>
+#include <LibAudio/Loader.h>
+#include <LibAudio/WavWriter.h>
+#include <LibCore/ArgsParser.h>
+#include <LibCore/DeprecatedFile.h>
+#include <LibCore/System.h>
+#include <LibMain/Main.h>
+#include <stdio.h>
+
+static ErrorOr<StringView> guess_format_from_extension(StringView path)
+{
+    if (path == "-"sv)
+        return Error::from_string_view("Cannot guess format for standard stream, please specify format manually"sv);
+
+    LexicalPath lexical_path { path };
+    auto extension = lexical_path.extension();
+    if (extension.is_empty())
+        return Error::from_string_view("Cannot guess format for file without file extension"sv);
+
+    // Note: Do not return the `extension` StringView in any case, since that will possibly lead to UAF.
+    if (extension == "wav"sv || extension == "wave"sv)
+        return "wav"sv;
+    if (extension == "flac"sv)
+        return "flac"sv;
+    if (extension == "mp3"sv || extension == "mpeg3"sv)
+        return "mp3"sv;
+    if (extension == "qoa"sv)
+        return "qoa"sv;
+
+    return Error::from_string_view("Cannot guess format for the given file extension"sv);
+}
+
+static ErrorOr<Audio::PcmSampleFormat> parse_sample_format(StringView textual_format)
+{
+    if (textual_format == "u8"sv)
+        return Audio::PcmSampleFormat::Uint8;
+    if (textual_format == "s16le"sv)
+        return Audio::PcmSampleFormat::Int16;
+    if (textual_format == "s24le"sv)
+        return Audio::PcmSampleFormat::Int24;
+    if (textual_format == "s32le"sv)
+        return Audio::PcmSampleFormat::Int32;
+    if (textual_format == "f32le"sv)
+        return Audio::PcmSampleFormat::Float32;
+    if (textual_format == "f64le"sv)
+        return Audio::PcmSampleFormat::Float64;
+    return Error::from_string_view("Unknown sample format"sv);
+}
+
+ErrorOr<int> serenity_main(Main::Arguments arguments)
+{
+    TRY(Core::System::pledge("stdio rpath wpath cpath"));
+
+    StringView input {};
+    StringView output {};
+    StringView input_format {};
+    StringView output_format {};
+    StringView output_sample_format;
+
+    Core::ArgsParser args_parser;
+    args_parser.set_general_help("Convert between audio formats");
+    args_parser.add_option(input, "Audio file to convert (or '-' for standard input)", "input", 'i', "input");
+    args_parser.add_option(input_format, "Force input codec and container (see manual for supported codecs and containers)", "input-audio-codec", 0, "input-codec");
+    args_parser.add_option(output_format, "Set output codec", "audio-codec", 0, "output-codec");
+    args_parser.add_option(output_sample_format, "Set output sample format (see manual for supported formats)", "audio-format", 0, "sample-format");
+    args_parser.add_option(output, "Target file (or '-' for standard output)", "output", 'o', "output");
+    args_parser.parse(arguments);
+
+    if (input.is_empty())
+        return Error::from_string_view("Input file is required, use '-' to read from standard input"sv);
+
+    if (output_format.is_empty() && output == "-"sv)
+        return Error::from_string_view("Output format must be specified manually when writing to standard output"sv);
+
+    if (input != "-"sv)
+        TRY(Core::System::unveil(Core::DeprecatedFile::absolute_path(input), "r"sv));
+    if (output != "-"sv)
+        TRY(Core::System::unveil(Core::DeprecatedFile::absolute_path(output), "rwc"sv));
+    TRY(Core::System::unveil(nullptr, nullptr));
+
+    RefPtr<Audio::Loader> input_loader;
+    // Use normal loader infrastructure to guess input format.
+    if (input_format.is_empty()) {
+        auto loader_or_error = Audio::Loader::create(input);
+        if (loader_or_error.is_error()) {
+            warnln("Could not guess codec for input file '{}'. Try forcing a codec with '--i:c:a'", input);
+            return 1;
+        }
+        input_loader = loader_or_error.release_value();
+    } else {
+        warnln("Forcing input codec is not supported");
+        return 1;
+    }
+    VERIFY(input_loader);
+
+    if (output_format.is_empty())
+        output_format = TRY(guess_format_from_extension(output));
+    VERIFY(!output_format.is_empty());
+
+    if (output_format == "wav"sv) {
+        Optional<NonnullOwnPtr<Audio::WavWriter>> writer;
+        if (!output.is_empty()) {
+            auto parsed_output_sample_format = input_loader->pcm_format();
+            if (!output_sample_format.is_empty())
+                parsed_output_sample_format = TRY(parse_sample_format(output_sample_format));
+
+            writer.emplace(TRY(Audio::WavWriter::create_from_file(
+                output,
+                static_cast<int>(input_loader->sample_rate()),
+                input_loader->num_channels(),
+                parsed_output_sample_format)));
+        }
+        if (output != "-"sv)
+            out("Writing: \033[s");
+
+        while (input_loader->loaded_samples() < input_loader->total_samples()) {
+            auto samples_or_error = input_loader->get_more_samples();
+            if (samples_or_error.is_error()) {
+                warnln("Error while loading samples: {} (at {})", samples_or_error.error().description, samples_or_error.error().index);
+                return 1;
+            }
+            auto samples = samples_or_error.release_value();
+            if (writer.has_value())
+                TRY((*writer)->write_samples(samples.span()));
+            // TODO: Show progress updates like aplay by moving the progress calculation into a common utility function.
+            if (output != "-"sv) {
+                out("\033[u{}/{}", input_loader->loaded_samples(), input_loader->total_samples());
+                fflush(stdout);
+            }
+        }
+
+        if (writer.has_value())
+            (*writer)->finalize();
+        if (output != "-"sv)
+            outln();
+    } else {
+        warnln("Codec {} is not supported for encoding", output_format);
+    }
+
+    return 0;
+}