As of 2017, two userspace library implementations are known; alsa-lib and tinyalsa. The latter is simple I/O library to use ALSA PCM interface. On the other hand, alsa-lib is more complicated than it. This is because it's designed to add features to transmission of data frames; e.g. sample resampling. To achieve this, alsa-lib has its configuration space and plugin system.
In aplay, some options are implemented as a flag for the plugins in alsa-lib. The flag is given to snd_pcm_open(). This commit adds support for the flags.
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- axfer/xfer-libasound.c | 25 +++++++++++++++++++++++++ axfer/xfer-libasound.h | 4 ++++ 2 files changed, 29 insertions(+)
diff --git a/axfer/xfer-libasound.c b/axfer/xfer-libasound.c index 1e709e0..a731423 100644 --- a/axfer/xfer-libasound.c +++ b/axfer/xfer-libasound.c @@ -13,6 +13,10 @@ enum no_short_opts { // 200 or later belong to non us-ascii character set. OPT_PERIOD_SIZE = 200, OPT_BUFFER_SIZE, + OPT_DISABLE_RESAMPLE, + OPT_DISABLE_CHANNELS, + OPT_DISABLE_FORMAT, + OPT_DISABLE_SOFTVOL, OPT_FATAL_ERRORS, OPT_TEST_NOWAIT, }; @@ -29,6 +33,11 @@ static const struct option l_opts[] = { {"avail-min", 1, 0, 'A'}, {"start-delay", 1, 0, 'R'}, {"stop-delay", 1, 0, 'T'}, + // For plugins in alsa-lib. + {"disable-resample", 0, 0, OPT_DISABLE_RESAMPLE}, + {"disable-channels", 0, 0, OPT_DISABLE_CHANNELS}, + {"disable-format", 0, 0, OPT_DISABLE_FORMAT}, + {"disable-softvol", 0, 0, OPT_DISABLE_SOFTVOL}, // For debugging. {"fatal-errors", 0, 0, OPT_FATAL_ERRORS}, {"test-nowait", 0, 0, OPT_TEST_NOWAIT}, @@ -77,6 +86,14 @@ static int xfer_libasound_parse_opt(struct xfer_context *xfer, int key, state->msec_for_start_threshold = arg_parse_decimal_num(optarg, &err); else if (key == 'T') state->msec_for_stop_threshold = arg_parse_decimal_num(optarg, &err); + else if (key == OPT_DISABLE_RESAMPLE) + state->no_auto_resample = true; + else if (key == OPT_DISABLE_CHANNELS) + state->no_auto_channels = true; + else if (key == OPT_DISABLE_FORMAT) + state->no_auto_format = true; + else if (key == OPT_DISABLE_SOFTVOL) + state->no_softvol = true; else if (key == OPT_FATAL_ERRORS) state->finish_at_xrun = true; else if (key == OPT_TEST_NOWAIT) @@ -164,6 +181,14 @@ static int open_handle(struct xfer_context *xfer)
if (state->nonblock) mode |= SND_PCM_NONBLOCK; + if (state->no_auto_resample) + mode |= SND_PCM_NO_AUTO_RESAMPLE; + if (state->no_auto_channels) + mode |= SND_PCM_NO_AUTO_CHANNELS; + if (state->no_auto_format) + mode |= SND_PCM_NO_AUTO_FORMAT; + if (state->no_softvol) + mode |= SND_PCM_NO_SOFTVOL;
err = snd_pcm_open(&state->handle, state->node_literal, xfer->direction, mode); diff --git a/axfer/xfer-libasound.h b/axfer/xfer-libasound.h index 113c1b9..cf940e5 100644 --- a/axfer/xfer-libasound.h +++ b/axfer/xfer-libasound.h @@ -43,6 +43,10 @@ struct libasound_state { bool nonblock:1; bool mmap:1; bool test_nowait:1; + bool no_auto_resample:1; + bool no_auto_channels:1; + bool no_auto_format:1; + bool no_softvol:1;
bool use_waiter:1; };