Add new prebuffer filter.

This could be handy for lossy networks that require a lot of buffering
in addition to methods (like FEC) to cope with packet loss.

diff --git a/NEWS b/NEWS
index c444464fe9c75d7f2ead98e0e100f30508f3387a..e51de1b7ad21e0170c561702130cf8346e886447 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,7 @@ NEWS
 -------------------------------------------------
 
        - the new oss writer (supported on *BSD and Linux)
+       - the new prebuffer filter
        - improved signal handling
        - variable fec output buffer size
 

diff --git a/configure.ac b/configure.ac
index d158fd3de4cc12b117455c4fe41214da756729d5..85a327297042c4430721c707be7f0ba3adcd7215 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -84,7 +84,7 @@ dccp_send fd user_list chunk_queue afs osl aft mood score attribute blob ringbuf
 playlist sha1 rbtree sched audiod grab_client filter_common wav_filter compress_filter
 http_recv dccp_recv recv_common write_common file_write audiod_command
 client_common recv stdout filter stdin audioc write client fsck exec send_common ggo
-udp_recv udp_send color fec fecdec_filter"
+udp_recv udp_send color fec fecdec_filter prebuffer_filter"
 
 all_executables="server recv filter audioc write client fsck afh"
 
@@ -96,11 +96,13 @@ recv_ldflags=""
 receivers=" http dccp udp"
 senders=" http dccp udp"
 
-filter_cmdline_objs="filter.cmdline compress_filter.cmdline amp_filter.cmdline"
+filter_cmdline_objs="filter.cmdline compress_filter.cmdline amp_filter.cmdline
+       prebuffer_filter.cmdline"
 filter_errlist_objs="filter_common wav_filter compress_filter filter string
-       stdin stdout sched fd amp_filter ggo fecdec_filter fec"
+       stdin stdout sched fd amp_filter ggo fecdec_filter fec
+       prebuffer_filter time"
 filter_ldflags=""
-filters=" compress wav amp fecdec"
+filters=" compress wav amp fecdec prebuffer"
 
 audioc_cmdline_objs="audioc.cmdline"
 audioc_errlist_objs="audioc string net fd"
@@ -108,11 +110,12 @@ audioc_ldflags=""
 
 audiod_cmdline_objs="audiod.cmdline grab_client.cmdline compress_filter.cmdline
        http_recv.cmdline dccp_recv.cmdline file_write.cmdline client.cmdline
-       audiod_command_list amp_filter.cmdline udp_recv.cmdline"
+       audiod_command_list amp_filter.cmdline udp_recv.cmdline
+       prebuffer_filter.cmdline"
 audiod_errlist_objs="audiod signal string daemon stat net
        time grab_client filter_common wav_filter compress_filter amp_filter http_recv dccp_recv
        recv_common fd sched write_common file_write audiod_command crypt fecdec_filter
-       client_common ggo udp_recv color fec"
+       client_common ggo udp_recv color fec prebuffer_filter"
 audiod_ldflags=""
 audiod_audio_formats=""
 

diff --git a/error.h b/error.h
index fbc6c4dec89641e49ae4a492bb63dec9565fa2ba..c53ab89a3b15192285de2f13048c4340c1fcd070 100644 (file)
--- a/error.h
+++ b/error.h
@@ -34,6 +34,9 @@ DEFINE_ERRLIST_OBJECT_ENUM;
 
 extern const char **para_errlist[];
 
+#define PREBUFFER_FILTER_ERRORS \
+       PARA_ERROR(PREBUFFER_SYNTAX, "syntax error in prebuffer filter config"), \
+
 #define OSS_WRITE_ERRORS \
        PARA_ERROR(BAD_SAMPLE_FORMAT, "sample format not supported"), \
        PARA_ERROR(BAD_CHANNEL_COUNT, "channel count not supported"), \

diff --git a/ggo/prebuffer_filter.ggo b/ggo/prebuffer_filter.ggo
new file mode 100644 (file)
index 0000000..7553e95
--- /dev/null
+++ b/ggo/prebuffer_filter.ggo
@@ -0,0 +1,24 @@
+option "duration" d
+#~~~~~~~~~~~~~~~~~~
+"prebuffer time"
+int typestr="milliseconds"
+default="200"
+optional
+details="
+       Wait that many milliseconds before letting data go through.
+       The time interval starts when the first data byte is seen by
+       this filter.
+"
+
+option "size" s
+#~~~~~~~~~~~~~~
+"amount of data to prebuffer"
+int typestr="bytes"
+default="0"
+optional
+details="
+       Wait until that many data bytes are available in the input buffer.
+       The default value of zero means to not prebuffer by size at all.
+       If both --duration and --size options are given and non-zero, the
+       filter waits until both conditions are met.
+"

diff --git a/prebuffer_filter.c b/prebuffer_filter.c
new file mode 100644 (file)
index 0000000..759991e
--- /dev/null
+++ b/prebuffer_filter.c
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2009 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file prebuffer_filter.c Paraslash's prebuffering filter. */
+
+#include "para.h"
+#include "prebuffer_filter.cmdline.h"
+#include "list.h"
+#include "sched.h"
+#include "ggo.h"
+#include "filter.h"
+#include "string.h"
+#include "error.h"
+
+/** Data specific to the prebuffer filter. */
+struct private_prebuffer_data {
+       /** The configuration data for this instance of the filter. */
+       struct prebuffer_filter_args_info *conf;
+       /** Number of bytes prebuffered or -1 if no longer prebuffering. */
+       int prebuffered;
+       /** End of prebuffering period. */
+       struct timeval barrier;
+};
+
+static ssize_t prebuffer_convert(char *inbuf, size_t inbuf_len,
+               struct filter_node *fn)
+{
+       struct private_prebuffer_data *ppd = fn->private_data;
+       struct prebuffer_filter_args_info *conf = ppd->conf;
+
+       if (inbuf_len == 0) {
+               if (*fn->fc->input_error < 0 && ppd->prebuffered >= 0)
+                       goto prebuffer_end;
+               return 0;
+       }
+       if (ppd->prebuffered < 0) {
+               size_t copy = PARA_MIN(inbuf_len, fn->bufsize - fn->loaded);
+               memcpy(fn->buf + fn->loaded, inbuf, copy);
+               fn->loaded += copy;
+               return copy;
+       }
+       if (ppd->prebuffered + inbuf_len > fn->bufsize) {
+               fn->bufsize = PARA_MAX(2 * fn->bufsize,
+                       ppd->prebuffered + inbuf_len);
+               fn->buf = para_realloc(fn->buf, fn->bufsize);
+       }
+       memcpy(fn->buf + ppd->prebuffered, inbuf, inbuf_len);
+       if (ppd->prebuffered == 0) {
+               struct timeval tv;
+               PARA_INFO_LOG("prebuffer period %dms\n",
+                       conf->duration_arg);
+               ms2tv(conf->duration_arg, &tv);
+               tv_add(&tv, now, &ppd->barrier);
+       }
+       ppd->prebuffered += inbuf_len;
+       PARA_DEBUG_LOG("%zu bytes prebuffered\n", ppd->prebuffered);
+       if (*fn->fc->input_error >= 0) {
+               struct timeval diff;
+               if (tv_diff(now, &ppd->barrier, &diff) < 0)
+                       goto out;
+               if (ppd->prebuffered < conf->size_arg)
+                       goto out;
+       }
+prebuffer_end:
+       fn->loaded = ppd->prebuffered;
+       ppd->prebuffered = -1;
+out:
+       return inbuf_len;
+}
+
+static void prebuffer_close(struct filter_node *fn)
+{
+       free(fn->private_data);
+       free(fn->buf);
+}
+
+static int prebuffer_parse_config(int argc, char **argv, void **config)
+{
+       struct prebuffer_filter_args_info *prebuffer_conf
+               = para_calloc(sizeof(*prebuffer_conf));
+       int ret = -E_PREBUFFER_SYNTAX;
+
+       if (prebuffer_cmdline_parser(argc, argv, prebuffer_conf))
+               goto err;
+       ret = -ERRNO_TO_PARA_ERROR(EINVAL);
+       if (prebuffer_conf->duration_arg < 0)
+               goto err;
+       if (prebuffer_conf->size_arg < 0)
+               goto err;
+       PARA_NOTICE_LOG("prebuffering %ims, %i bytes\n",
+               prebuffer_conf->duration_arg, prebuffer_conf->size_arg);
+       *config = prebuffer_conf;
+       return 1;
+err:
+       free(prebuffer_conf);
+       return ret;
+}
+
+static void prebuffer_open(struct filter_node *fn)
+{
+       struct private_prebuffer_data *ppd = para_calloc(sizeof(*ppd));
+
+       ppd->conf = fn->conf;
+       fn->private_data = ppd;
+       fn->bufsize = 8192; /* gets increased on demand */
+       fn->buf = para_malloc(fn->bufsize);
+}
+
+/**
+ * The init function of the prebuffer filter.
+ *
+ * \param f Pointer to the struct to initialize.
+ */
+void prebuffer_filter_init(struct filter *f)
+{
+       struct prebuffer_filter_args_info dummy;
+
+       prebuffer_cmdline_parser_init(&dummy);
+       f->open = prebuffer_open;
+       f->close = prebuffer_close;
+       f->convert = prebuffer_convert;
+       f->parse_config = prebuffer_parse_config;
+       f->help = (struct ggo_help) {
+               .short_help = prebuffer_filter_args_info_help,
+               .detailed_help = prebuffer_filter_args_info_detailed_help
+       };
+}