X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=53854e08c012dd7952df4d94ce50dae987dc004a;hp=88e48b4524717bc832201d7e5c5cac75976abffc;hb=dc26e5bc49d839fd966b7ad6f596e444ac8908d3;hpb=d46a0767b58654f15f16406cf99296287bd0d534

diff --git a/alsa_write.c b/alsa_write.c
index 88e48b45..53854e08 100644
--- 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);
 }