[alsa-devel] ALSA / Soundcard latency
Hello, My company is a supplier of car manufacturers. We develop and produce digital audio amplifiers. We would like to build our test setup for echo order cancelation routines for our audio amplifiers with a real- time Linux and ALSA. We have very strong requirements regarding the maximum latency from audio input via line in to audio output. We would like to achieve a maximum latency < 1ms. The alsaloop example mentions a latency of 1 ms which is on our test setup with the latest rt kernel from This Mächler not working due to broken pipe errors. Is 1 ms feasible with a standard PC ? Currently we still don´t know what the lowest possible latency using ALSA is. We tried different soundcards and found out that they have an internal FIFO, which seems to be one of the limiting factors. The min. latency we can achieve is currently 5,6 ms, but this is still to high. Is there any possibility to switch this FIFO off via ALSA ? Is it possible at all to achieve such low latency values ? Kind regards, ___________________________________________________________________________________ Feilmeier Daniel R&D Software Electronics Tel.: +49-9962-2003-629 Fax.: +49-9962-2003-79 E-Mail: FeilmeierD@askgroup.de<mailto:FeilmeierD@askgroup.de> ASK Industries GmbH Hauptstrasse 73 D-94559 Niederwinkling HRG Straubing HRB 10703 Geschaeftsfuehrer: Ruggero Marchetti Franz Maier Juergen Pledl ___________________________________________________________________________________
Feilmeier Daniel (Ask De) wrote:
We have very strong requirements regarding the maximum latency from audio input via line in to audio output. We would like to achieve a maximum latency < 1ms. The alsaloop example mentions a latency of 1 ms which is on our test setup
What hardware? USB and FireWire have long packet queues.
We tried different soundcards and found out that they have an internal FIFO, which seems to be one of the limiting factors.
What are the numbers? What settings did you use for alsaloop? Regards, Clemens
participants (2)
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Clemens Ladisch -
Feilmeier Daniel (Ask De)