X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=vss.c;h=21ac37470e4748ea407fd7bacb96dfb42f3ee55a;hp=25082834eb0160de013dd11639f3354160ee261b;hb=e386c19376fa959b91710145923149d2d5dfbb29;hpb=e56d454fbd865f34cb5e043ff43585754631b079

diff --git a/vss.c b/vss.c
index 25082834..21ac3747 100644
--- a/vss.c
+++ b/vss.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1997-2010 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 1997-2011 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -129,6 +129,8 @@ struct fec_group {
 	struct timeval slice_duration;
 	/** Group contains the audio file header that occupies that many slices. */
 	uint8_t num_header_slices;
+	/** Number of bytes per slice for this group. */
+	uint16_t slice_bytes;
 };
 
 enum fec_client_state {
@@ -209,47 +211,68 @@ static void write_fec_header(struct fec_client *fc, struct vss_task *vsst)
 	write_u32(buf + 14, g->bytes);
 
 	write_u8(buf + 18, fc->current_slice_num);
-	write_u16(buf + 20, fc->mps - FEC_HEADER_SIZE);
+	write_u8(buf + 19, 0); /* unused */
+	write_u16(buf + 20, g->slice_bytes);
 	write_u8(buf + 22, g->first_chunk? 0 : 1);
 	write_u8(buf + 23, vsst->header_len? 1 : 0);
-	memset(buf + 24, 0, 7);
+	memset(buf + 24, 0, 8);
 }
 
-static int need_audio_header(struct fec_client *fc, struct vss_task *vsst)
+static bool need_audio_header(struct fec_client *fc, struct vss_task *vsst)
 {
 	if (!mmd->current_chunk) {
 		tv_add(now, &vsst->header_interval, &fc->next_header_time);
-		return 0;
+		return false;
 	}
 	if (!vsst->header_buf)
-		return 0;
-	if (!vsst->header_len)
-		return 0;
-	if (fc->group.num && tv_diff(&fc->next_header_time, now, NULL) > 0)
-		return 0;
+		return false;
+	if (vsst->header_len == 0)
+		return false;
+	if (fc->group.num > 0) {
+		if (!fc->fcp->need_periodic_header)
+			return false;
+		if (tv_diff(&fc->next_header_time, now, NULL) > 0)
+			return false;
+	}
 	tv_add(now, &vsst->header_interval, &fc->next_header_time);
-	return 1;
+	return true;
 }
 
-static int num_slices(long unsigned bytes, int mps, int rs)
+static bool need_data_slices(struct fec_client *fc, struct vss_task *vsst)
+{
+	if (fc->group.num > 0)
+		return true;
+	if (!vsst->header_buf)
+		return true;
+	if (vsst->header_len == 0)
+		return true;
+	if (fc->fcp->need_periodic_header)
+		return true;
+	return false;
+}
+
+static int num_slices(long unsigned bytes, int max_payload, int rs)
 {
-	int m = mps - FEC_HEADER_SIZE;
 	int ret;
 
-	assert(m > 0);
+	assert(max_payload > 0);
 	assert(rs > 0);
-	ret = DIV_ROUND_UP(bytes, m);
+	ret = DIV_ROUND_UP(bytes, max_payload);
 	if (ret + rs > 255)
 		return -E_BAD_CT;
 	return ret;
 }
 
 /* set group start and group duration */
-static void set_group_timing(struct fec_client *fc, struct fec_group *g)
+static void set_group_timing(struct fec_client *fc, struct vss_task *vsst)
 {
+	struct fec_group *g = &fc->group;
 	struct timeval *chunk_tv = vss_chunk_time();
 
-	tv_scale(g->num_chunks, chunk_tv, &g->duration);
+	if (!need_data_slices(fc, vsst))
+		ms2tv(200, &g->duration);
+	else
+		tv_scale(g->num_chunks, chunk_tv, &g->duration);
 	tv_divide(fc->fcp->slices_per_group + fc->num_extra_slices,
 		&g->duration, &g->slice_duration);
 	PARA_DEBUG_LOG("durations (group/chunk/slice): %lu/%lu/%lu\n",
@@ -258,7 +281,7 @@ static void set_group_timing(struct fec_client *fc, struct fec_group *g)
 
 static int initialize_fec_client(struct fec_client *fc, struct vss_task *vsst)
 {
-	int k, n, ret, mps;
+	int k, n, ret;
 	int hs, ds, rs; /* header/data/redundant slices */
 	struct fec_client_parms *fcp = fc->fcp;
 
@@ -272,59 +295,192 @@ static int initialize_fec_client(struct fec_client *fc, struct vss_task *vsst)
 		ret = fcp->init_fec(fc->sc);
 		if (ret < 0)
 			return ret;
-		mps = ret;
+		fc->mps = ret;
 	} else
-		mps = generic_max_transport_msg_size(fc->sc->fd);
-	if (mps <= FEC_HEADER_SIZE)
+		fc->mps = generic_max_transport_msg_size(fc->sc->fd);
+	if (fc->mps <= FEC_HEADER_SIZE)
 		return -ERRNO_TO_PARA_ERROR(EINVAL);
 
 	rs = fc->fcp->slices_per_group - fc->fcp->data_slices_per_group;
-	ret = num_slices(vsst->header_len, mps, rs);
+	ret = num_slices(vsst->header_len, fc->mps - FEC_HEADER_SIZE, rs);
 	if (ret < 0)
-		goto err;
+		return ret;
 	hs = ret;
-	ret = num_slices(afh_get_largest_chunk_size(&mmd->afd.afhi),
-		mps, rs);
+	ret = num_slices(mmd->afd.max_chunk_size, fc->mps - FEC_HEADER_SIZE, rs);
 	if (ret < 0)
-		goto err;
+		return ret;
 	ds = ret;
-	k = ret + ds;
+	if (fc->fcp->need_periodic_header)
+		k = hs + ds;
+	else
+		k = PARA_MAX(hs, ds);
 	if (k < fc->fcp->data_slices_per_group)
 		k = fc->fcp->data_slices_per_group;
+	fc->num_extra_slices = k - fc->fcp->data_slices_per_group;
 	n = k + rs;
-	PARA_CRIT_LOG("hs: %d, ds: %d, rs: %d, k: %d, n: %d\n", hs, ds, rs, k, n);
 	fec_free(fc->parms);
 	ret = fec_new(k, n, &fc->parms);
 	if (ret < 0)
 		return ret;
-	fc->num_extra_slices = k - fc->fcp->data_slices_per_group;
-	PARA_NOTICE_LOG("fec parms %d:%d:%d (%d extra slices)\n",
-		mps, k, n, fc->num_extra_slices);
+	PARA_INFO_LOG("mps: %d, k: %d, n: %d, extra slices: %d\n",
+		fc->mps, k, n, fc->num_extra_slices);
 	fc->src_data = para_realloc(fc->src_data, k * sizeof(char *));
-	fc->enc_buf = para_realloc(fc->enc_buf, mps);
-	memset(fc->enc_buf, 0, mps);
-	fc->extra_src_buf = para_realloc(fc->extra_src_buf, mps);
-	memset(fc->extra_src_buf, 0, mps);
+	fc->enc_buf = para_realloc(fc->enc_buf, fc->mps);
+	fc->extra_src_buf = para_realloc(fc->extra_src_buf, fc->mps);
 
-	fc->mps = mps;
 	fc->state = FEC_STATE_READY_TO_RUN;
 	fc->next_header_time.tv_sec = 0;
 	fc->stream_start = *now;
 	fc->first_stream_chunk = mmd->current_chunk;
 	return 1;
-err:
-	fec_free(fc->parms);
-	return ret;
+}
+
+static void compute_group_size(struct vss_task *vsst, struct fec_group *g,
+		int max_bytes)
+{
+	int i, max_chunks = PARA_MAX(1LU, 150 / tv2ms(vss_chunk_time()));
+
+	g->num_chunks = 0;
+	g->bytes = 0;
+	/*
+	 * Include chunks into the group until the group duration is at least
+	 * 150ms.  For ogg and wma, a single chunk's duration (ogg page/wma
+	 * super frame) is already larger than 150ms, so a FEC group consists
+	 * of exactly one chunk for these audio formats.
+	 */
+	for (i = 0;; i++) {
+		const char *buf;
+		size_t len;
+		int chunk_num = g->first_chunk + i;
+
+		if (g->bytes > 0 && i >= max_chunks) /* duration limit */
+			break;
+		if (chunk_num >= mmd->afd.afhi.chunks_total) /* eof */
+			break;
+		afh_get_chunk(chunk_num, &mmd->afd.afhi, vsst->map, &buf, &len);
+		if (g->bytes + len > max_bytes)
+			break;
+		/* Include this chunk */
+		g->bytes += len;
+		g->num_chunks++;
+	}
+	assert(g->num_chunks);
+}
+
+/*
+ * Compute the slice size of the next group.
+ *
+ * The FEC parameters n and k are fixed but the slice size varies per
+ * FEC group.  We'd like to choose slices as small as possible to avoid
+ * unnecessary FEC calculations but large enough to guarantee that the
+ * k data slices suffice to encode the header (if needed) and the data
+ * chunk(s).
+ *
+ * Once we know the payload of the next group, we define the number s
+ * of bytes per slice for this group by
+ *
+ * 	s = ceil(payload / k)
+ *
+ * However, for header streams, computing s is more complicated since no
+ * overlapping of header and data slices is possible. Hence we have k >=
+ * 2 and s must satisfy
+ *
+ * (*)	ceil(h / s) + ceil(d / s) <= k
+ *
+ * where h and d are payload of the header and the data chunk(s)
+ * respectively. In general there is no value for s such that (*)
+ * becomes an equality, for example if h = 4000, d = 5000 and k = 10.
+ *
+ * We use the following approach for computing a suitable value for s:
+ *
+ * Let
+ * 	k1 := ceil(k * min(h, d) / (h + d)),
+ * 	k2 := k - k1.
+ *
+ * Note that k >= 2 implies k1 > 0 and k2 > 0, so
+ *
+ * 	s := max(ceil(min(h, d) / k1), ceil(max(h, d) / k2))
+ *
+ * is well-defined. Inequality (*) holds for this value of s since k1
+ * slices suffice to store min(h, d) while k2 slices suffice to store
+ * max(h, d), i.e. the first addent of (*) is bounded by k1 and the
+ * second by k2.
+ *
+ * For the above example we obtain
+ *
+ * 	k1 = ceil(10 * 4000 / 9000) = 5, k2 = 5,
+ * 	s = max(4000 / 5, 5000 / 5) = 1000,
+ *
+ * which is optimal since a slice size of 999 bytes would already require
+ * 11 slices.
+ */
+static int compute_slice_size(struct fec_client *fc, struct vss_task *vsst)
+{
+	struct fec_group *g = &fc->group;
+	int k = fc->fcp->data_slices_per_group + fc->num_extra_slices;
+	int n = fc->fcp->slices_per_group + fc->num_extra_slices;
+	int ret, k1, k2, h, d, min, max, sum;
+	int max_slice_bytes = fc->mps - FEC_HEADER_SIZE;
+	int max_group_bytes;
+
+	if (!need_audio_header(fc, vsst)) {
+		max_group_bytes = k * max_slice_bytes;
+		g->num_header_slices = 0;
+		compute_group_size(vsst, g, max_group_bytes);
+		g->slice_bytes = DIV_ROUND_UP(g->bytes, k);
+		if (g->slice_bytes == 0)
+			g->slice_bytes = 1;
+		return 1;
+	}
+	if (!need_data_slices(fc, vsst)) {
+		g->bytes = 0;
+		g->num_chunks = 0;
+		g->slice_bytes = DIV_ROUND_UP(vsst->header_len, k);
+		g->num_header_slices = k;
+		return 1;
+	}
+	h = vsst->header_len;
+	max_group_bytes = (k - num_slices(h, max_slice_bytes, n - k))
+		* max_slice_bytes;
+	compute_group_size(vsst, g, max_group_bytes);
+	d = g->bytes;
+	if (d == 0) {
+		g->slice_bytes = DIV_ROUND_UP(h, k);
+		ret = num_slices(vsst->header_len, g->slice_bytes, n - k);
+		if (ret < 0)
+			return ret;
+		g->num_header_slices = ret;
+		return 1;
+	}
+	min = PARA_MIN(h, d);
+	max = PARA_MAX(h, d);
+	sum = h + d;
+	k1 = DIV_ROUND_UP(k * min, sum);
+	k2 = k - k1;
+	assert(k1 > 0);
+	assert(k2 > 0);
+
+	g->slice_bytes = PARA_MAX(DIV_ROUND_UP(min, k1), DIV_ROUND_UP(max, k2));
+	/*
+	 * This value of s := g->slice_bytes satisfies inequality (*) above,
+	 * but it might be larger than max_slice_bytes. However, we know that
+	 * max_slice_bytes are sufficient to store header and data, so:
+	 */
+	g->slice_bytes = PARA_MIN((int)g->slice_bytes, max_slice_bytes);
+
+	ret = num_slices(vsst->header_len, g->slice_bytes, n - k);
+	if (ret < 0)
+		return ret;
+	g->num_header_slices = ret;
+	return 1;
 }
 
 static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 {
 	int ret, i, k, n, data_slices;
 	size_t len;
-	const char *buf, *start_buf;
+	const char *buf;
 	struct fec_group *g = &fc->group;
-	unsigned slice_bytes;
-	uint32_t max_data_size;
 
 	if (fc->state == FEC_STATE_NONE) {
 		ret = initialize_fec_client(fc, vsst);
@@ -333,7 +489,6 @@ static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 		g->first_chunk = mmd->current_chunk;
 		g->num = 0;
 		g->start = *now;
-		
 	} else {
 		struct timeval tmp;
 		if (g->first_chunk + g->num_chunks >= mmd->afd.afhi.chunks_total)
@@ -344,75 +499,64 @@ static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 		 */
 		tmp = g->start;
 		tv_add(&tmp, &g->duration, &g->start);
-		set_group_timing(fc, g);
+		set_group_timing(fc, vsst);
 		g->first_chunk += g->num_chunks;
 		g->num++;
 	}
-	slice_bytes = fc->mps - FEC_HEADER_SIZE;
-	PARA_CRIT_LOG("slice_bytes: %d\n", slice_bytes);
 	k = fc->fcp->data_slices_per_group + fc->num_extra_slices;
 	n = fc->fcp->slices_per_group + fc->num_extra_slices;
-	PARA_CRIT_LOG("k: %d, n: %d\n", k, n);
-	if (need_audio_header(fc, vsst)) {
-		ret = num_slices(vsst->header_len, slice_bytes, n - k);
-		if (ret < 0)
-			return ret;
-		g->num_header_slices = ret;
-	} else
-		g->num_header_slices = 0;
-	afh_get_chunk(g->first_chunk, &mmd->afd.afhi, vsst->map, &start_buf,
-		&len);
-	data_slices = k - g->num_header_slices;
-	assert(data_slices);
-	max_data_size = slice_bytes * data_slices;
-	g->bytes = 0;
-	for (i = g->first_chunk; i < mmd->afd.afhi.chunks_total; i++) {
-		afh_get_chunk(i, &mmd->afd.afhi, vsst->map, &buf, &len);
-		if (g->bytes + len > max_data_size)
-			break;
-		g->bytes += len;
-	}
-	g->num_chunks = i - g->first_chunk;
-	assert(g->num_chunks);
+
+	compute_slice_size(fc, vsst);
+	assert(g->slice_bytes > 0);
+	ret = num_slices(g->bytes, g->slice_bytes, n - k);
+	if (ret < 0)
+		return ret;
+	data_slices = ret;
+	assert(g->num_header_slices + data_slices <= k);
 	fc->current_slice_num = 0;
 	if (g->num == 0)
-		set_group_timing(fc, g);
+		set_group_timing(fc, vsst);
 
 	/* setup header slices */
 	buf = vsst->header_buf;
 	for (i = 0; i < g->num_header_slices; i++) {
 		fc->src_data[i] = (const unsigned char *)buf;
-		buf += slice_bytes;
+		buf += g->slice_bytes;
 	}
 
 	/* setup data slices */
-	buf = start_buf;
-	for (i = g->num_header_slices; i < k; i++) {
-		if (buf + slice_bytes > vsst->map + mmd->size)
+	afh_get_chunk(g->first_chunk, &mmd->afd.afhi, vsst->map, &buf, &len);
+	for (; i < g->num_header_slices + data_slices; i++) {
+		if (buf + g->slice_bytes > vsst->map + mmd->size) {
 			/*
 			 * Can not use the memory mapped audio file for this
 			 * slice as it goes beyond the map. This slice will not
 			 * be fully used.
 			 */
+			uint32_t payload_size = vsst->map + mmd->size - buf;
+			memcpy(fc->extra_src_buf, buf, payload_size);
+			if (payload_size < g->slice_bytes)
+				memset(fc->extra_src_buf + payload_size, 0,
+					g->slice_bytes - payload_size);
+			fc->src_data[i] = fc->extra_src_buf;
+			i++;
 			break;
+		}
 		fc->src_data[i] = (const unsigned char *)buf;
-		buf += slice_bytes;
+		buf += g->slice_bytes;
 	}
 	if (i < k) {
-		uint32_t payload_size = vsst->map + mmd->size - buf;
-		memcpy(fc->extra_src_buf, buf, payload_size);
-		fc->src_data[i] = fc->extra_src_buf;
-		i++;
 		/* use arbitrary data for all remaining slices */
 		buf = vsst->map;
 		for (; i < k; i++)
 			fc->src_data[i] = (const unsigned char *)buf;
 	}
-	PARA_DEBUG_LOG("FEC group %d: %d chunks (%d - %d), "
-		"%d header slices, %d data slices\n",
+	PARA_DEBUG_LOG("FEC group %d: %d chunks (%d - %d), %d bytes\n",
 		g->num, g->num_chunks, g->first_chunk,
-		g->first_chunk + g->num_chunks - 1,
-		g->num_header_slices, data_slices
+		g->first_chunk + g->num_chunks - 1, g->bytes
+	);
+	PARA_DEBUG_LOG("slice_bytes: %d, %d header slices, %d data slices\n",
+		g->slice_bytes, g->num_header_slices, data_slices
 	);
 	return 1;
 }
@@ -433,7 +577,7 @@ static int compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst)
 	}
 	write_fec_header(fc, vsst);
 	fec_encode(fc->parms, fc->src_data, fc->enc_buf + FEC_HEADER_SIZE,
-		fc->current_slice_num, fc->mps - FEC_HEADER_SIZE);
+		fc->current_slice_num, fc->group.slice_bytes);
 	return 1;
 }
 
@@ -884,8 +1028,9 @@ static void vss_send(struct vss_task *vsst)
 		if (compute_next_fec_slice(fc, vsst) <= 0)
 			continue;
 		PARA_DEBUG_LOG("sending %d:%d (%u bytes)\n", fc->group.num,
-			fc->current_slice_num, fc->mps);
-		fc->fcp->send_fec(fc->sc, (char *)fc->enc_buf, fc->mps);
+			fc->current_slice_num, fc->group.slice_bytes);
+		fc->fcp->send_fec(fc->sc, (char *)fc->enc_buf,
+			fc->group.slice_bytes + FEC_HEADER_SIZE);
 		fc->current_slice_num++;
 		fec_active = 1;
 	}