alsa: Improve documentation of struct private_alsa_write_data.

[paraslash.git] / alsa_write.c

diff --git a/alsa_write.c b/alsa_write.c
index 88e48b4524717bc832201d7e5c5cac75976abffc..53854e08c012dd7952df4d94ce50dae987dc004a 100644 (file)
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -34,16 +34,21 @@ struct private_alsa_write_data {
        snd_pcm_t *handle;
        /** Determined and set by alsa_init(). */
        int bytes_per_frame;
-       /**
-        * The sample rate given by command line option or the decoder
-        * of the writer node group.
+       /*
+        * If the sample rate is not given at the command line and no wav
+        * header was detected, the btr exec mechanism is employed to query the
+        * ancestor buffer tree nodes for this information. In a typical setup
+        * the decoder passes the sample rate back to the alsa writer.
+        *
+        *  \sa \ref btr_exec_up().
         */
        unsigned sample_rate;
-       snd_pcm_format_t sample_format;
-       /**
-        * The number of channels, given by command line option or the
-        * decoder of the writer node group.
+       /*
+        * The sample format (8/16 bit, signed/unsigned, little/big endian) is
+        * determined in the same way as the \a sample_rate.
         */
+       snd_pcm_format_t sample_format;
+       /* The number of channels, again determined like \a sample_rate. */
        unsigned channels;
        struct timeval drain_barrier;
        /* File descriptor for select(). */
@@ -211,7 +216,6 @@ static void alsa_write_pre_select(struct sched *s, struct task *t)
        if (ret < 0) {
                PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
                        snd_strerror(-ret));
-               t->error = -E_ALSA;
                return;
        }
        pad->poll_fd = pfd.fd;
@@ -361,9 +365,6 @@ void alsa_write_init(struct writer *w)
        w->post_select = alsa_write_post_select;
        w->parse_config_or_die = alsa_parse_config_or_die;
        w->free_config = alsa_free_config;
-       w->help = (struct ggo_help) {
-               .short_help = alsa_write_args_info_help,
-               .detailed_help = alsa_write_args_info_detailed_help
-       };
+       w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write);
        alsa_write_cmdline_parser_free(&dummy);
 }