Note that this only happened after disabling flat-volumes. This is from currently recording into Audacity, and using pavucontrol to change the source output volume. I: alsa-sink.c: Increasing minimal latency to 2.00 ms D: alsa-sink.c: Latency set to 20.00ms D: alsa-sink.c: hwbuf_unused=349272 D: alsa-sink.c: setting avail_min=87760 D: alsa-sink.c: Latency set to 20.00ms D: alsa-sink.c: hwbuf_unused=349272 D: alsa-sink.c: setting avail_min=87760 D: protocol-native.c: Client pavucontrol changes volume of source output ALSA Capture. E: sample-util.c: Assertion 'c->length % pa_frame_size(spec) == 0' failed at pulsecore/sample-util.c:737, function pa_volume_memchunk(). Aborting. Program received signal SIGABRT, Aborted. [Switching to Thread 0x7fffeceb8700 (LWP 4790)] 0x00007ffff663ec55 in raise () from /lib/x86_64-linux-gnu/libc.so.6 (gdb) bt full #0 0x00007ffff663ec55 in raise () from /lib/x86_64-linux-gnu/libc.so.6 No symbol table info available. #1 0x00007ffff6642a06 in abort () from /lib/x86_64-linux-gnu/libc.so.6 No symbol table info available. #2 0x00007ffff7b82fa7 in pa_volume_memchunk (c=0x7fffeceb7cd0, spec=0x88d724, volume=0x88d69c) at pulsecore/sample-util.c:736 ptr = <value optimized out> linear = {{f = 1.23594525e-42, i = 882}, {f = 0, i = 0}, {f = -5.90432221e+33, i = 4153511299}, {f = 4.59163468e-41, i = 32767}, {f = -7.34647593e+33, i = 4155841224}, {f = 4.59163468e-41, i = 32767}, {f = -5.91324343e+33, i = 4153525712}, {f = 4.59163468e-41, i = 32767}, {f = 1.76628907e-39, i = 1260466}, {f = 0, i = 0}, { f = -5.88461049e+33, i = 4153479453}, {f = 4.59163468e-41, i = 32767}, {f = nan(0x7fffff), i = 2147483647}, {f = 0, i = 0}, {f = 8.98059676e-39, i = 6408768}, {f = 0, i = 0}, {f = 1.23594525e-42, i = 882}, {f = 0, i = 0}, { f = -5.90901462e+33, i = 4153518880}, {f = 4.59163468e-41, i = 32767}, {f = 1.22487387e-38, i = 8740992}, {f = 0, i = 0}, {f = 1.22487387e-38, i = 8740992}, {f = 0, i = 0}, {f = -7.34647593e+33, i = 4155841224}, {f = 4.59163468e-41, i = 32767}, {f = -5.91324343e+33, i = 4153525712}, {f = 4.59163468e-41, i = 32767}, {f = 0, i = 0}, {f = 0, i = 0}, { f = 1.23594525e-42, i = 882}, {f = 0, i = 0}, {f = 8.98059676e-39, i = 6408768}, {f = 0, i = 0}, {f = 0, i = 0}, { f = 0, i = 0}, {f = 1.25646026e-38, i = 8966400}, {f = 0, i = 0}, {f = -5.90925912e+33, i = 4153519275}, { f = 4.59163468e-41, i = 32767}, {f = 1.76752502e-39, i = 1261348}, {f = 0, i = 0}, {f = 1.25375183e-38, i = 8947072}, { f = 0, i = 0}, {f = 1.23594525e-42, i = 882}, {f = 0, i = 0}, {f = -5.91387478e+33, i = 4153526732}, { f = 4.59163468e-41, i = 32767}, {f = 1.22768543e-38, i = 8761056}, {f = 0, i = 0}, {f = -5.8559429e+33, i = 4153433138}, {f = 4.59163468e-41, i = 32767}, {f = -2.27749582e+27, i = 3974855888}, {f = 4.59163468e-41, i = 32767}, {f = -7.77774515e+28, i = 4017836032}, {f = 4.59163468e-41, i = 32767}, {f = -9.70501044e+33, i = 4159651642}, {f = 4.59163468e-41, i = 32767}, {f = -5.91959839e+33, i = 4153535979}, {f = 4.59163468e-41, i = 32767}, {f = 1.23594525e-42, i = 882}, {f = 0, i = 0}, {f = 1.2564894e-38, i = 8966608}, {f = 0, i = 0}} do_volume = <value optimized out> __func__ = "pa_volume_memchunk" __PRETTY_FUNCTION__ = "pa_volume_memchunk" #3 0x00007ffff7ba34b8 in pa_source_output_push (o=0x88d1d0, chunk=<value optimized out>) at pulsecore/source-output.c:750 qchunk = {memblock = 0x7fffef7b5000, index = 0, length = 882} nvfs = false need_volume_factor_source = false volume_is_norm = false length = <value optimized out> limit = 0 mbs = 0 __func__ = "pa_source_output_push" __PRETTY_FUNCTION__ = "pa_source_output_push" #4 0x00007ffff7ba9651 in pa_source_post (s=0x7fffe8022e50, chunk=0x7fffeceb7e00) at pulsecore/source.c:874 o = 0x88d1d0 state = 0xffffffffffffffff __func__ = "pa_source_post" ---Type <return> to continue, or q <return> to quit--- __PRETTY_FUNCTION__ = "pa_source_post" #5 0x00007fffedee025f in mmap_read (userdata=0x7fffe80083c0) at modules/alsa/alsa-source.c:583 chunk = {memblock = 0x87c240, index = 0, length = 882} err = <value optimized out> frames = 441 sframes = <value optimized out> p = <value optimized out> areas = 0x889870 offset = 42909 n = <value optimized out> n_bytes = 882 r = <value optimized out> after_avail = false process_usec = 10000 work_done = false max_sleep_usec = 10000 left_to_record = <value optimized out> j = 1 #6 thread_func (userdata=0x7fffe80083c0) at modules/alsa/alsa-source.c:1375 work_done = <value optimized out> sleep_usec = 0 on_timeout = <value optimized out> ret = <value optimized out> rtpoll_sleep = 0 u = 0x7fffe80083c0 revents = 0 __func__ = "thread_func" __PRETTY_FUNCTION__ = "thread_func" #7 0x00007ffff7932d28 in internal_thread_func (userdata=0x7fffe80050b0) at pulsecore/thread-posix.c:83 t = 0x7fffe80050b0 #8 0x00007ffff7048d8c in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0 No symbol table info available. #9 0x00007ffff66f11dd in clone () from /lib/x86_64-linux-gnu/libc.so.6 No symbol table info available. #10 0x0000000000000000 in ?? () No symbol table info available. -- David Henningsson, Canonical Ltd. http://launchpad.net/~diwic