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Subsonic API: added flac transcoding + now select the source bitrate by default when transcoding from lossy to lossy to avoid maxing the output bitrate, fixes #797

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This commit is contained in:
emeric
2026-01-04 16:22:53 +01:00
parent d45ccb8c2c
commit c39a26c4f6
1 changed files with 62 additions and 19 deletions
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src/libs/subsonic/impl/endpoints/MediaRetrieval.cpp
+62 -19
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@@ -26,6 +26,7 @@
#include "core/ILogger.hpp"
#include "core/IResourceHandler.hpp"
#include "core/String.hpp"
#include "core/media/Codec.hpp"
#include "core/media/MimeType.hpp"
#include "database/Session.hpp"
@@ -57,9 +58,10 @@ namespace lms::api::subsonic
core::media::Codec codec;
};
constexpr std::array outputFormats{
OutputFormat{ "mp3", core::media::Container::MPEG, core::media::Codec::MP3 },
OutputFormat{ "opus", core::media::Container::Ogg, core::media::Codec::Opus },
OutputFormat{ "vorbis", core::media::Container::Ogg, core::media::Codec::Vorbis },
OutputFormat{ .name = "mp3", .container = core::media::Container::MPEG, .codec = core::media::Codec::MP3 },
OutputFormat{ .name = "opus", .container = core::media::Container::Ogg, .codec = core::media::Codec::Opus },
OutputFormat{ .name = "vorbis", .container = core::media::Container::Ogg, .codec = core::media::Codec::Vorbis },
OutputFormat{ .name = "flac", .container = core::media::Container::FLAC, .codec = core::media::Codec::FLAC },
};
std::optional<OutputFormat> getOutputFormatByName(std::string_view format)
@@ -80,7 +82,7 @@ namespace lms::api::subsonic
return res;
}
std::optional<OutputFormat> userTranscodeFormatToOutputFormat(db::TranscodingOutputFormat format)
OutputFormat userTranscodeFormatToOutputFormat(db::TranscodingOutputFormat format)
{
std::optional<OutputFormat> res;
@@ -97,7 +99,11 @@ namespace lms::api::subsonic
break;
}
return res;
if (!res)
throw InternalErrorGenericError{ "User's default transcoding format is invalid" };
LMS_LOG(API_SUBSONIC, DEBUG, "Using user's default transcoding format: " << res->name);
return *res;
}
struct StreamParameters
@@ -119,44 +125,63 @@ namespace lms::api::subsonic
const AudioFileId audioId{ trackId ? AudioFileId{ *trackId } : AudioFileId{ *podcastEpisodeId } };
// Optional params
std::size_t maxBitRate{ getParameterAs<std::size_t>(context.getParameters(), "maxBitRate").value_or(0) * 1000 }; // "If set to zero, no limit is imposed", given in kpbs
const std::size_t maxBitRate{ getParameterAs<std::size_t>(context.getParameters(), "maxBitRate").value_or(0) * 1000 }; // "If set to zero, no limit is imposed", given in kpbs
const std::string format{ getParameterAs<std::string>(context.getParameters(), "format").value_or("") };
std::size_t timeOffset{ getParameterAs<std::size_t>(context.getParameters(), "timeOffset").value_or(0) };
bool estimateContentLength{ getParameterAs<bool>(context.getParameters(), "estimateContentLength").value_or(false) };
const std::size_t timeOffset{ getParameterAs<std::size_t>(context.getParameters(), "timeOffset").value_or(0) };
const bool estimateContentLength{ getParameterAs<bool>(context.getParameters(), "estimateContentLength").value_or(false) };
const AudioFileInfo audioFileInfo{ getAudioFileInfo(context.getDbSession(), audioId) };
StreamParameters parameters;
parameters.audioProperties = audioFileInfo.audioProperties;
parameters.filePath = audioFileInfo.path;
parameters.estimateContentLength = estimateContentLength;
if (format == "raw") // raw => no transcoding
return parameters; // TODO: what if offset is not 0?
std::optional<OutputFormat> requestedFormat{ getOutputFormatByName(format) };
std::optional<OutputFormat> requestedFormat;
if (!format.empty())
{
requestedFormat = getOutputFormatByName(format);
if (!requestedFormat)
LMS_LOG(API_SUBSONIC, ERROR, "Format '" << format << "' is not recognized: ignoring");
}
if (!requestedFormat)
{
if (context.getUser()->getSubsonicEnableTranscodingByDefault())
requestedFormat = userTranscodeFormatToOutputFormat(context.getUser()->getSubsonicDefaultTranscodingOutputFormat());
}
if (requestedFormat && core::media::getCodecDesc(requestedFormat->codec).isLossless)
{
if (maxBitRate > 0)
throw BadParameterGenericError{ "maxBitRate", "Cannot limit bitrate when requesting a lossless format" };
// we accept to transcode from a lossy format to a lossless one
}
if (!requestedFormat && (maxBitRate == 0 || audioFileInfo.audioProperties.bitrate <= maxBitRate))
{
LMS_LOG(API_SUBSONIC, DEBUG, "File's bitrate is compatible with parameters => no transcoding");
LMS_LOG(API_SUBSONIC, DEBUG, "File's bitrate (" << audioFileInfo.audioProperties.bitrate << " bps) is compatible with parameters => no transcoding");
return parameters; // no transcoding needed
}
// Check if the input file is compatible with the actual requested format
// same codec => apply max bitrate
// otherwise => apply default bitrate (because we can't really compare bitrates between formats) + max bitrate)
std::size_t bitrate{};
// Check if the input file is compatible with the requested format
std::optional<std::size_t> bitrate;
if (requestedFormat && requestedFormat->container == audioFileInfo.audioProperties.container && requestedFormat->codec == audioFileInfo.audioProperties.codec)
{
// same codec => check if compatible with max bitrate
if (maxBitRate == 0 || audioFileInfo.audioProperties.bitrate <= maxBitRate)
{
LMS_LOG(API_SUBSONIC, DEBUG, "File's bitrate and format are compatible with parameters => no transcoding");
LMS_LOG(API_SUBSONIC, DEBUG, "File's bitrate (" << audioFileInfo.audioProperties.bitrate << " bps) and format are compatible with parameters => no transcoding");
return parameters; // no transcoding needed
}
// otherwise => apply requested bitrate
assert(maxBitRate > 0);
bitrate = maxBitRate;
}
@@ -165,10 +190,26 @@ namespace lms::api::subsonic
if (!requestedFormat) // no format provided => use user's default
requestedFormat = userTranscodeFormatToOutputFormat(context.getUser()->getSubsonicDefaultTranscodingOutputFormat());
if (!bitrate) // no bitrate provided => use user's default
bitrate = context.getUser()->getSubsonicDefaultTranscodingOutputBitrate();
if (maxBitRate) // but still honor provided maxBitRate, if any
bitrate = std::min<std::size_t>(bitrate, maxBitRate);
assert(requestedFormat);
if (!core::media::getCodecDesc(requestedFormat->codec).isLossless)
{
// Try to keep a bitrate as close as possible to the source one
// If the source is lossless, we need to pick a default bitrate
if (core::media::getCodecDesc(audioFileInfo.audioProperties.codec).isLossless)
{
bitrate = context.getUser()->getSubsonicDefaultTranscodingOutputBitrate();
LMS_LOG(API_SUBSONIC, DEBUG, "Source is lossless, selecting user's default transcoding bitrate (" << *bitrate << " bps) for transcoding");
}
else
{
bitrate = audioFileInfo.audioProperties.bitrate;
LMS_LOG(API_SUBSONIC, DEBUG, "Source is lossy, selecting source bitrate (" << *bitrate << " bps) for transcoding");
}
if (maxBitRate > 0) // Honor provided maxBitRate, if any
bitrate = std::min<std::size_t>(*bitrate, maxBitRate);
}
transcodeParameters.inputParameters.filePath = audioFileInfo.path;
transcodeParameters.inputParameters.audioProperties = audioFileInfo.audioProperties;
@@ -181,6 +222,8 @@ namespace lms::api::subsonic
transcodeParameters.outputParameters.stripMetadata = false; // We want clients to use metadata (offline use, replay gain, etc.)
LMS_LOG(API_SUBSONIC, DEBUG, "Transcoding to format '" << requestedFormat->name << "'" << (bitrate ? (" with bitrate " + std::to_string(*bitrate) + " bps") : ""));
return parameters;
}
} // namespace