From 760238fe16e496eeb8ecbc4ca8784a3deb76e52e Mon Sep 17 00:00:00 2001 From: Max Kellermann Date: Wed, 1 Jul 2020 17:53:23 +0200 Subject: [PATCH] decoder/opus: apply pre-skip (RFC7845 4.2) Fixes the first part of https://github.com/MusicPlayerDaemon/MPD/issues/867 --- NEWS | 2 ++ src/decoder/plugins/OpusDecoderPlugin.cxx | 35 ++++++++++++++++------- 2 files changed, 27 insertions(+), 10 deletions(-) diff --git a/NEWS b/NEWS index 308e70712..703ce8478 100644 --- a/NEWS +++ b/NEWS @@ -4,6 +4,8 @@ ver 0.21.25 (not yet released) * input - file: detect premature end of file - smbclient: don't send credentials to MPD clients +* decoder + - opus: apply pre-skip * output - osx: improve sample rate selection * Windows/Android: diff --git a/src/decoder/plugins/OpusDecoderPlugin.cxx b/src/decoder/plugins/OpusDecoderPlugin.cxx index 8a262b901..9043d76c0 100644 --- a/src/decoder/plugins/OpusDecoderPlugin.cxx +++ b/src/decoder/plugins/OpusDecoderPlugin.cxx @@ -75,6 +75,8 @@ class MPDOpusDecoder final : public OggDecoder { OpusDecoder *opus_decoder = nullptr; opus_int16 *output_buffer = nullptr; + unsigned pre_skip, skip; + /** * If non-zero, then a previous Opus stream has been found * already with this number of channels. If opus_decoder is @@ -136,11 +138,13 @@ MPDOpusDecoder::OnOggBeginning(const ogg_packet &packet) if (opus_decoder != nullptr || !IsOpusHead(packet)) throw std::runtime_error("BOS packet must be OpusHead"); - unsigned channels, pre_skip; + unsigned channels; if (!ScanOpusHeader(packet.packet, packet.bytes, channels, pre_skip) || !audio_valid_channel_count(channels)) throw std::runtime_error("Malformed BOS packet"); + skip = pre_skip; + assert(opus_decoder == nullptr); assert(IsInitialized() == (output_buffer != nullptr)); @@ -236,15 +240,25 @@ MPDOpusDecoder::HandleAudio(const ogg_packet &packet) opus_strerror(nframes)); if (nframes > 0) { + if (skip >= (unsigned)nframes) { + skip -= nframes; + return; + } + + const opus_int16 *data = output_buffer; + data += skip * previous_channels; + nframes -= skip; + skip = 0; + const size_t nbytes = nframes * frame_size; auto cmd = client.SubmitData(input_stream, - output_buffer, nbytes, + data, nbytes, 0); if (cmd != DecoderCommand::NONE) throw cmd; if (packet.granulepos > 0) - client.SubmitTimestamp(FloatDuration(packet.granulepos) + client.SubmitTimestamp(FloatDuration(packet.granulepos - pre_skip) / opus_sample_rate); } } @@ -260,6 +274,7 @@ MPDOpusDecoder::Seek(uint64_t where_frame) try { SeekGranulePos(where_granulepos); + skip = pre_skip; return true; } catch (...) { return false; @@ -302,10 +317,9 @@ mpd_opus_stream_decode(DecoderClient &client, static bool ReadAndParseOpusHead(OggSyncState &sync, OggStreamState &stream, - unsigned &channels) + unsigned &channels, unsigned &pre_skip) { ogg_packet packet; - unsigned pre_skip; return OggReadPacket(sync, stream, packet) && packet.b_o_s && IsOpusHead(packet) && @@ -329,11 +343,12 @@ ReadAndVisitOpusTags(OggSyncState &sync, OggStreamState &stream, static void VisitOpusDuration(InputStream &is, OggSyncState &sync, OggStreamState &stream, - TagHandler &handler) + ogg_int64_t pre_skip, TagHandler &handler) { ogg_packet packet; - if (OggSeekFindEOS(sync, stream, packet, is)) { + if (OggSeekFindEOS(sync, stream, packet, is) && + packet.granulepos >= pre_skip) { const auto duration = SongTime::FromScale(packet.granulepos, opus_sample_rate); @@ -353,15 +368,15 @@ mpd_opus_scan_stream(InputStream &is, TagHandler &handler) noexcept OggStreamState os(first_page); - unsigned channels; - if (!ReadAndParseOpusHead(oy, os, channels) || + unsigned channels, pre_skip; + if (!ReadAndParseOpusHead(oy, os, channels, pre_skip) || !ReadAndVisitOpusTags(oy, os, handler)) return false; handler.OnAudioFormat(AudioFormat(opus_sample_rate, SampleFormat::S16, channels)); - VisitOpusDuration(is, oy, os, handler); + VisitOpusDuration(is, oy, os, pre_skip, handler); return true; }