Beginning Of Tracks Cut Off

[RussellS]

Hi, firstly let me say that the issue I am experiencing is not exclusive to RuneAudio and is in fact also present in Volumio as well so it may well be an issue with MPD. However it may be that I need to configure something differently which is why I am asking here. I have also posted this in the Volumio forum as well but have had no response.

I am having an issue whereby when I select an individual track to play the first fraction of a second of the track is cut off. This obviously isn't a problem when there is some lead in silence but on tracks where the music starts immediately then it is very annoying because the start of the song is cut off.

However this does not happen if the track is in a playlist (other than the first song), in this situation the transition from the previous track to this one is fine and nothing is cut off. It only appears to be the first track in a playlist or an individual track that exhibits this problem. Also it doesn't appear to matter what format the track is in either, flac, mp3 and ogg files seem to exhibit the same behaviour. Also it does not make any difference if I play the files directly from the library or if I use RuneAudio as a DLNA renderer controlled from JRiver Media Center, the start of the track is still cut of in both cases.

The system in question is a Raspberry Pi (model B) with an Audiophonics ES9023 I2s DAC. The audio files are stored on a server.

I've searched the forum but cannot find any references to this problem which makes me think that it maybe a configuration issue or something I'm doing wrong.

If anyone has any suggestions I would be most grateful.

Thanks

[ACX]

Hi RusselS,
have you already tried to tweak the values of "Audio buffer size" and "Buffer before play" options in the MPD section? Do they introduce any change in the behaviour?

[RussellS]

Hi, thanks for the reply.

I have raised the "Audio buffer size" to 4096 and the "Buffer before play" value to 30% but it has not made any noticeable change to the behaviour.

[RussellS]

Hi again, I just thought I'd do some tests to confirm what I'm hearing and to actually put a figure on how much is actually missing from the beginning of the audio track.

So I recorded the output from the DAC into Audacity and then opened the original FLAC file to compare and this is the result:



So the top two traces are the original FLAC file and the bottom two are the output from the dac which I time shifted in Audacity so that they lined up perfectly. When I zoom in I can see that it is actually 0.4s that is missing from the beginning of the track.

Obviously on the vast majority of tracks it is not an issue because they either have a second or so lead in silence or they fade in. It is just the few tracks that start abruptly that cause an issue and then only if they are the first track in a playlist. As it happens the track I selected for this test is the first track on an album so always exhibits this behaviour when I listen to the complete album.

Anyway, I hope this provides some usefull information.

Regards

[ACX]

Does it also happen with tracks in other position across the queue if you leave the player stopped for a while (try with different steps: from some seconds to a minute) and then you press play again?

[RussellS]

Yes, it happens with any track in any position if I stop and then restart it again. It doesn't matter if I restart after 1 second or 1 minute the result is the same with first 0.4s cut off. However, if I just let the playlist play through the tracks then they all play fine and the transitions between tracks are smooth and gapless with nothing cut off.

[ACX]

It sounds like your DAC has a sort of "mute" feature which is activated when no I2S clock is detected (usually to protect the DAC from spikes and avoid bumps), and it's slow to detect when the signal comes back. When MPD is stopped in ALSA the signal is off, there's no "keepalive". I have a very similar behavior with a S/PDIF DAC which has a protection relay that intervents every time the digital signal is 0 for a while.
I suggest you to contact the manufacturer and ask him about that...

[nopap]

Hi,
For the report, I have the same behavior with my pi connected to Pionner AV amp via HDMI: Beginning of tracks cutoff.
I have the same behavior with my media center connected to the same amp also via HDMI... so i guess an amp problem as ACX mentioned.
I haven't tried using a spdif connection to see if there is any difference.

Regards
Emmanuel

[RussellS]