In ALSA PCM interface, some parameters are used to configure runtime of PCM substream independently of actual hardware. These parameters are mainly used to decide the detailed timing to start/stop PCM substream and release I/O blocking state of application. These parameters are represented and delivered by a structure.
In alsa-lib PCM API, the structure is hidden from userspace applications. The applications can set/get actual parameters by helper functions.
In aplay, three of the parameters are configurable. This commit adds support for them. When no options are given, default values are used.
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- axfer/options.c | 11 +++++++- axfer/options.h | 4 +++ axfer/xfer-libasound.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 86 insertions(+), 3 deletions(-)
diff --git a/axfer/options.c b/axfer/options.c index 5d5dda89..aaeba5f2 100644 --- a/axfer/options.c +++ b/axfer/options.c @@ -322,7 +322,7 @@ void context_options_calculate_duration(struct context_options *opts, int context_options_init(struct context_options *opts, int argc, char *const *argv, snd_pcm_stream_t direction) { - static const char *s_opts = "hvqd:s:t:ID:f:c:r:NMF:B:"; + static const char *s_opts = "hvqd:s:t:ID:f:c:r:NMF:B:A:R:T:"; static const struct option l_opts[] = { /* For generic purposes. */ {"help", 0, 0, 'h'}, @@ -345,6 +345,9 @@ int context_options_init(struct context_options *opts, int argc, {"buffer-time", 1, 0, 'B'}, {"period-size", 1, 0, OPT_PERIOD_SIZE}, {"buffer-size", 1, 0, OPT_BUFFER_SIZE}, + {"avail-min", 1, 0, 'A'}, + {"start-delay", 1, 0, 'R'}, + {"stop-delay", 1, 0, 'T'}, /* For debugging. */ {"dump-hw-params", 0, 0, OPT_DUMP_HW_PARAMS}, {"fatal-errors", 0, 0, OPT_FATAL_ERRORS}, @@ -400,6 +403,12 @@ int context_options_init(struct context_options *opts, int argc, opts->frames_per_period = parse_l(optarg, &err); else if (c == OPT_BUFFER_SIZE) opts->frames_per_buffer = parse_l(optarg, &err); + else if (c == 'A') + opts->msec_for_avail_min = parse_l(optarg, &err); + else if (c == 'R') + opts->msec_for_start_threshold = parse_l(optarg, &err); + else if (c == 'T') + opts->msec_for_stop_threshold = parse_l(optarg, &err); else if (c == OPT_DUMP_HW_PARAMS) opts->dump_hw_params = true; else if (c == OPT_FATAL_ERRORS) diff --git a/axfer/options.h b/axfer/options.h index f4ac6c64..63b36364 100644 --- a/axfer/options.h +++ b/axfer/options.h @@ -41,6 +41,10 @@ struct context_options { unsigned int frames_per_period; unsigned int frames_per_buffer;
+ unsigned int msec_for_avail_min; + unsigned int msec_for_start_threshold; + unsigned int msec_for_stop_threshold; + /* For debugging. */ bool dump_hw_params; bool finish_at_xrun; diff --git a/axfer/xfer-libasound.c b/axfer/xfer-libasound.c index 54c58b04..40222e91 100644 --- a/axfer/xfer-libasound.c +++ b/axfer/xfer-libasound.c @@ -338,8 +338,76 @@ static int retrieve_actual_hw_params(snd_pcm_hw_params_t *hw_params,
static int configure_sw_params(struct libasound_state *state, unsigned int frames_per_second, - unsigned int frames_per_buffer) + unsigned int frames_per_buffer, + unsigned int msec_for_avail_min, + unsigned int msec_for_start_threshold, + unsigned int msec_for_stop_threshold) { + snd_pcm_uframes_t frame_count; + int err; + + if (msec_for_avail_min > 0) { + frame_count = msec_for_avail_min * frames_per_second / 1000000; + if (frame_count == 0 || frame_count > frames_per_buffer) { + logging(state, + _("The msec for 'avail_min' is too %s: %u " + "msec (%lu frames at %u).\n"), + frame_count == 0 ? "small" : "large", + msec_for_avail_min, frame_count, + frames_per_second); + return -EINVAL; + } + err = snd_pcm_sw_params_set_avail_min(state->handle, + state->sw_params, frame_count); + if (err < 0) { + logging(state, + _("Fail to configure 'avail-min'.\n")); + return -EINVAL; + } + } + + if (msec_for_start_threshold > 0) { + frame_count = msec_for_start_threshold * frames_per_second / + 1000000; + if (frame_count == 0 || frame_count > frames_per_buffer) { + logging(state, + _("The msec for 'start-delay' is too %s: %u " + "msec (%lu frames at %u).\n"), + frame_count == 0 ? "small" : "large", + msec_for_start_threshold, frame_count, + frames_per_second); + return -EINVAL; + } + err = snd_pcm_sw_params_set_start_threshold(state->handle, + state->sw_params, frame_count); + if (err < 0) { + logging(state, + _("Fail to configure 'start-delay'.\n")); + return -EINVAL; + } + } + + if (msec_for_stop_threshold > 0) { + frame_count = msec_for_stop_threshold * frames_per_second / + 1000000; + if (frame_count == 0 || frame_count > frames_per_buffer) { + logging(state, + _("The msec for 'stop-delay' is too %s: %u " + "msec (%lu frames at %u).\n"), + frame_count == 0 ? "small" : "large", + msec_for_stop_threshold, frame_count, + frames_per_second); + return -EINVAL; + } + err = snd_pcm_sw_params_set_stop_threshold(state->handle, + state->sw_params, frame_count); + if (err < 0) { + logging(state, + _("Fail to configure 'stop-delay'.\n")); + return -EINVAL; + } + } + return snd_pcm_sw_params(state->handle, state->sw_params); }
@@ -404,7 +472,9 @@ static int xfer_libasound_pre_process(struct xfer_context *xfer, return err;
err = configure_sw_params(state, *frames_per_second, - *frames_per_buffer); + *frames_per_buffer, opts->msec_for_avail_min, + opts->msec_for_start_threshold, + opts->msec_for_stop_threshold); if (err < 0) { logging(state, _("Current software parameters:\n")); snd_pcm_sw_params_dump(state->sw_params, state->log);