X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fecdec_filter.c;h=ca9dcd739e23c6fe7e89d4ff67cec41686906318;hp=6ca0b037da0f55be826137facc4632415648329c;hb=bb6721e17e741b7ea52fbf88661d2b177bed72c3;hpb=30496a3da233a6cfb0b1005b808e8d1064cb91ff

diff --git a/fecdec_filter.c b/fecdec_filter.c
index 6ca0b037..ca9dcd73 100644
--- a/fecdec_filter.c
+++ b/fecdec_filter.c
@@ -4,7 +4,9 @@
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
-/** \file fecdec_filter.c A filter fec-decodes an audio stream. */
+/** \file fecdec_filter.c A filter that fec-decodes an audio stream. */
+
+#include <regex.h>
 
 #include <dirent.h>
 #include "para.h"
@@ -27,8 +29,10 @@
  */
 #define NUM_FEC_GROUPS 3
 
-/** Size of the output buffer of the fecdec filter. */
-#define FECDEC_OUTBUF_SIZE (128 * 1024)
+/** Default size of the output buffer of the fecdec filter. */
+#define FECDEC_DEFAULT_OUTBUF_SIZE (3 * 1024)
+/** Maximal size of the output buffer of the fecdec filter. */
+#define FECDEC_MAX_OUTBUF_SIZE (1024 * 1024)
 
 /** Data read from the header of a slice. */
 struct fec_header {
@@ -46,6 +50,10 @@ struct fec_header {
 	uint8_t slice_num;
 	/** Used data bytes of this slice. */
 	uint16_t slice_bytes;
+	/** Non-zero if this group is the beginning of the stream. */
+	uint8_t bos;
+	/** Non-zero if this stream embedds audio headers into fec groups. */
+	uint8_t header_stream;
 };
 
 /**
@@ -64,6 +72,20 @@ struct fecdec_group {
 	unsigned char **data;
 };
 
+/**
+ * The fecdec filter defers decoding of the first group until the first slice
+ * of the next group was received. This avoids buffer underruns in subsequent
+ * filters of the filter chain.
+ */
+enum group_completion_status {
+	/** No complete group received so far. */
+	GCS_NO_COMPLETE_GROUP,
+	/** First group received, but not yet decoded. */
+	GCS_FIRST_GROUP_COMPLETE,
+	/** At least one complete group decoded. */
+	GCS_FIRST_GROUP_DECODED,
+};
+
 /**
  * Data private to the fecdec filter.
  */
@@ -72,6 +94,12 @@ struct private_fecdec_data {
 	struct fec_parms *fec;
 	/** Keeps track of what was received so far. */
 	struct fecdec_group groups[NUM_FEC_GROUPS];
+	/** Whether an audio file header was already received. */
+	int have_header;
+	/** See \ref group_completion_status. */
+	unsigned completion_status;
+	/** Points to the first received group. */
+	struct fecdec_group *first_complete_group;
 };
 
 /** Iterate over all fecdec groups. */
@@ -112,10 +140,15 @@ static int find_group(struct fec_header *h,
 	FOR_EACH_FECDEC_GROUP(fg, pfd) {
 		if (fg->h.group_num != h->group_num)
 			continue;
+		if (fg->num_received_slices == 0)
+			goto success;
 		if (fg->h.slices_per_group != h->slices_per_group)
-			continue;
+			return -E_BAD_FEC_HEADER;
 		if (fg->h.data_slices_per_group != h->data_slices_per_group)
-			continue;
+			return -E_BAD_FEC_HEADER;
+		if (fg->h.group_bytes != h->group_bytes)
+			return -E_BAD_FEC_HEADER;
+success:
 		*result = fg;
 		return 1;
 	}
@@ -140,6 +173,13 @@ static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 	FOR_EACH_FECDEC_GROUP(fg, pfd) {
 		if (!group_complete(fg))
 			continue;
+		/*
+		 * Don't clear the first complete group if it has not yet been
+		 * decoded.
+		 */
+		if (pfd->completion_status == GCS_FIRST_GROUP_COMPLETE
+				&& pfd->first_complete_group == fg)
+			continue;
 		clear_group(fg);
 		return fg;
 	}
@@ -156,8 +196,10 @@ static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 	}
 	if (!group_complete(oldest) && !group_empty(oldest))
 		PARA_WARNING_LOG("Clearing incomplete group %d "
-			"(contains %d slices)\n", fg->h.group_num,
-			fg->num_received_slices);
+			"(contains %d slices)\n", oldest->h.group_num,
+			oldest->num_received_slices);
+	assert(pfd->completion_status != GCS_FIRST_GROUP_COMPLETE
+		|| oldest != pfd->first_complete_group);
 	clear_group(oldest);
 	return oldest;
 }
@@ -198,6 +240,8 @@ static int add_slice(char *buf, struct fecdec_group *fg)
 	int r, slice_num;
 
 	if (group_complete(fg)) {
+		PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
+			fg->h.group_num, fg->h.slice_num);
 		fg->num_received_slices++;
 		return 0;
 	}
@@ -216,24 +260,69 @@ static int add_slice(char *buf, struct fecdec_group *fg)
 	return 1;
 }
 
+enum fec_group_usability {
+	FEC_GROUP_UNUSABLE,
+	FEC_GROUP_USABLE,
+	FEC_GROUP_USABLE_SKIP_HEADER,
+};
+
+static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
+		struct private_fecdec_data *pfd)
+{
+	struct fec_header *h = &fg->h;
+
+	if (!h->header_stream)
+		return FEC_GROUP_USABLE;
+	if (pfd->have_header) {
+		if (h->audio_header_size)
+			return FEC_GROUP_USABLE_SKIP_HEADER;
+		return FEC_GROUP_USABLE;
+	}
+	if (fg->h.bos)
+		return FEC_GROUP_USABLE;
+	if (fg->h.audio_header_size)
+		return FEC_GROUP_USABLE;
+	return FEC_GROUP_UNUSABLE;
+}
+
 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 {
 	int i, ret, sb = fg->h.slice_bytes;
-	size_t written = 0;
+	size_t written = 0, need;
 	struct private_fecdec_data *pfd = fn->private_data;
+	enum fec_group_usability u = group_is_usable(fg, pfd);
 
+	if (u == FEC_GROUP_UNUSABLE) {
+		PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
+		return 0;
+	}
+	PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
+		fg->h.data_slices_per_group);
 	ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 	if (ret < 0)
 		return ret;
+	pfd->have_header = 1;
+	i = 0;
+	if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
+		i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
+			/ fg->h.slice_bytes;
+		PARA_DEBUG_LOG("skipping %d header slices\n", i);
+	}
 	PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 		fg->h.group_num, fg->h.group_bytes,
 		fg->h.data_slices_per_group * sb);
-	for (i = 0; i < fg->h.data_slices_per_group; i++) {
+	need = fn->loaded + (fg->h.data_slices_per_group - i)* sb;
+	if (need > fn->bufsize) {
+		fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
+		if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
+			return -E_FECDEC_OVERRUN;
+		PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
+		fn->buf = para_realloc(fn->buf, fn->bufsize);
+	}
+	for (; i < fg->h.data_slices_per_group; i++) {
 		size_t n = sb;
 		if (n + written > fg->h.group_bytes)
 			n = fg->h.group_bytes - written;
-		if (fn->loaded + n > fn->bufsize)
-			return -E_FECDEC_OVERRUN;
 		memcpy(fn->buf + fn->loaded, fg->data[i], n);
 		fn->loaded += n;
 		written += n;
@@ -265,7 +354,9 @@ static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 
 	h->slice_num = read_u8(buf + 18);
 	h->slice_bytes = read_u16(buf + 20);
-	if (!h->group_bytes && & h->slice_bytes)
+	h->bos = read_u8(buf + 22);
+	h->header_stream = read_u8(buf + 23);
+	if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
 		return -E_FECDEC_EOF;
 //	PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 //		h->group_num, h->slice_num, h->slices_per_group);
@@ -277,7 +368,7 @@ static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 		struct filter_node *fn)
 {
 	struct fecdec_group *fg;
-	int ret;
+	int ret, k, n;
 	struct private_fecdec_data *pfd = fn->private_data;
 
 	if (h->slice_bytes > len) /* can not use the thing, try to read more */
@@ -285,30 +376,41 @@ static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 	ret = get_group(h, pfd, &fg);
 	if (ret < 0)
 		return ret;
-	if (group_complete(fg)) {
-		PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
-			h->slice_num);
+	if (!add_slice(buf, fg))
 		return 1;
-	}
-	ret = add_slice(buf, fg);
-	if (ret < 0)
-		return ret;
 	if (group_complete(fg)) {
-		if (!pfd->fec) {
-			int k = h->data_slices_per_group, n = h->slices_per_group;
-			PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
-			ret = fec_new(k, n, &pfd->fec);
-			if (ret < 0)
-				return ret;
+		if (pfd->completion_status == GCS_NO_COMPLETE_GROUP) {
+			pfd->completion_status = GCS_FIRST_GROUP_COMPLETE;
+			pfd->first_complete_group = fg;
+			return 1;
 		}
+		assert(pfd->fec);
 		ret = decode_group(fg, fn);
 		if (ret < 0)
 			return ret;
+		return 1;
 	}
+	if (pfd->completion_status == GCS_NO_COMPLETE_GROUP)
+		return 1;
+	if (pfd->completion_status == GCS_FIRST_GROUP_DECODED)
+		return 1;
+	if (fg == pfd->first_complete_group)
+		return 1;
+	assert(!pfd->fec);
+	k = h->data_slices_per_group;
+	n = h->slices_per_group;
+	PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
+	ret = fec_new(k, n, &pfd->fec);
+	if (ret < 0)
+		return ret;
+	ret = decode_group(pfd->first_complete_group, fn);
+	if (ret < 0)
+		return ret;
+	pfd->completion_status = GCS_FIRST_GROUP_DECODED;
 	return 1;
 }
 
-static int fecdec(char *buf, size_t len, struct filter_node *fn)
+static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
 {
 	int ret;
 	struct fec_header h;
@@ -316,7 +418,7 @@ static int fecdec(char *buf, size_t len, struct filter_node *fn)
 	ret = read_fec_header(buf, len, &h);
 	if (ret <= 0)
 		return ret;
-	if (h.slice_bytes > fn->bufsize)
+	if (!h.slice_bytes)
 		return -E_BAD_SLICE_SIZE;
 	if (h.slice_num > h.slices_per_group)
 		return -E_BAD_SLICE_NUM;
@@ -337,15 +439,19 @@ static void fecdec_close(struct filter_node *fn)
 		clear_group(fg);
 	free(fn->buf);
 	fn->buf = NULL;
+	fec_free(pfd->fec);
 	free(fn->private_data);
 	fn->private_data = NULL;
 }
 
 static void fecdec_open(struct filter_node *fn)
 {
-	fn->bufsize = FECDEC_OUTBUF_SIZE;
+	struct private_fecdec_data *pfd;
+	fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
 	fn->buf = para_malloc(fn->bufsize);
-	fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
+	pfd = para_calloc(sizeof(*pfd));
+	pfd->completion_status = GCS_NO_COMPLETE_GROUP;
+	fn->private_data = pfd;
 	fn->loaded = 0;
 }