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flvmux: Preallocate index space and fill it after finishing output

Browse source 
Make the index appear at the beginning of the file, which is what most
players are expecting.

Fixes #601236.
This commit is contained in:
Jan Urbański 2010-03-14 01:38:21 +01:00 committed by Sebastian Dröge
parent 7c74f7d525
commit 7deee29d2c
1 changed files with 106 additions and 71 deletions
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177
gst/flv/gstflvmux.c
View file

@ -50,6 +50,7 @@ enum
};
#define DEFAULT_IS_LIVE FALSE
#define MAX_INDEX_ENTRIES 128
static GstStaticPadTemplate src_templ = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
@ -566,6 +567,36 @@ gst_flv_mux_push (GstFlvMux * mux, GstBuffer * buffer)
return gst_pad_push (mux->srcpad, buffer);
}
static GstBuffer *
gst_flv_mux_preallocate_index (GstFlvMux * mux)
{
GstBuffer *tmp;
guint8 *data;
gint preallocate_size;
/* preallocate index of size:
* - 'keyframes' ECMA array key: 2 + 9 = 11 bytes
* - nested ECMA array header, length and end marker: 8 bytes
* - 'times' and 'filepositions' keys: 22 bytes
* - two strict arrays headers and lengths: 10 bytes
* - each index entry: 18 bytes
*/
preallocate_size = 11 + 8 + 22 + 10 + MAX_INDEX_ENTRIES * 18;
GST_DEBUG_OBJECT (mux, "preallocating %d bytes for the index",
preallocate_size);
tmp = gst_buffer_new_and_alloc (preallocate_size);
data = GST_BUFFER_DATA (tmp);
/* prefill the space with a gstfiller: <spaces> script tag variable */
GST_WRITE_UINT16_BE (data, 9); /* 9 characters */
memcpy (data + 2, "gstfiller", 9);
GST_WRITE_UINT8 (data + 11, 2); /* a string value */
GST_WRITE_UINT16_BE (data + 12, preallocate_size - 14);
memset (data + 14, ' ', preallocate_size - 14); /* the rest is spaces */
return tmp;
}
static GstFlowReturn
gst_flv_mux_write_metadata (GstFlvMux * mux)
{
@ -612,6 +643,13 @@ gst_flv_mux_write_metadata (GstFlvMux * mux)
GST_WRITE_UINT32_BE (data + 1, n_tags);
script_tag = gst_buffer_join (script_tag, tmp);
if (!mux->is_live) {
tmp = gst_flv_mux_preallocate_index (mux);
script_tag = gst_buffer_join (script_tag, tmp);
} else {
GST_DEBUG_OBJECT (mux, "not preallocating index, stream is live");
}
for (i = 0; tags && i < n_tags; i++) {
const gchar *tag_name =
gst_structure_nth_field_name ((const GstStructure *) tags, i);
@ -1010,113 +1048,110 @@ static GstFlowReturn
gst_flv_mux_write_index (GstFlvMux * mux)
{
GstFlowReturn ret = GST_FLOW_OK;
GstBuffer *script_tag, *tmp;
GstBuffer *index;
GstEvent *event;
guint8 *data;
GList *l;
guint32 index_len;
guint32 index_len, allocate_size;
guint32 i, index_skip;
if (!mux->index)
return GST_FLOW_OK;
script_tag = gst_buffer_new_and_alloc (11);
data = GST_BUFFER_DATA (script_tag);
if (mux->is_live)
return GST_FLOW_OK;
data[0] = 18;
/* Data size, unknown for now */
data[1] = 0;
data[2] = 0;
data[3] = 0;
/* Timestamp */
data[4] = data[5] = data[6] = data[7] = 0;
/* Stream ID */
data[8] = data[9] = data[10] = 0;
tmp = gst_buffer_new_and_alloc (13);
data = GST_BUFFER_DATA (tmp);
data[0] = 2; /* string */
data[1] = 0;
data[2] = 0x0a; /* length 10 */
memcpy (&data[3], "onMetaData", 10);
script_tag = gst_buffer_join (script_tag, tmp);
tmp = gst_buffer_new_and_alloc (5);
data = GST_BUFFER_DATA (tmp);
data[0] = 8; /* ECMA array */
GST_WRITE_UINT32_BE (data + 1, 2);
script_tag = gst_buffer_join (script_tag, tmp);
/* seek back to the preallocated index space */
event = gst_event_new_new_segment (FALSE, 1.0, GST_FORMAT_BYTES,
42, GST_CLOCK_TIME_NONE, 42);
if (!gst_pad_push_event (mux->srcpad, event)) {
GST_WARNING_OBJECT (mux, "Seek to rewrite index failed");
return GST_FLOW_OK;
}
mux->index = g_list_reverse (mux->index);
index_len = g_list_length (mux->index);
/* We write at most 128 elements */
index_skip = (index_len > 128) ? 1 + index_len / 128 : 1;
index_len =
(index_len <=
128) ? index_len : (index_len + index_skip - 1) / index_skip;
/* We write at most MAX_INDEX_ENTRIES elements */
if (index_len > MAX_INDEX_ENTRIES) {
index_skip = 1 + index_len / MAX_INDEX_ENTRIES;
index_len = (index_len + index_skip - 1) / index_skip;
} else {
index_skip = 1;
}
tmp = gst_buffer_new_and_alloc (2 + 5 + 1 + 4 + index_len * (1 + 8));
data = GST_BUFFER_DATA (tmp);
data[0] = 0; /* 5 bytes name */
data[1] = 5;
memcpy (&data[2], "times", 5);
data[7] = 10; /* array */
GST_WRITE_UINT32_BE (&data[8], index_len);
data += 12;
GST_DEBUG_OBJECT (mux, "Index length is %d", index_len);
/* see size calculation in gst_flv_mux_preallocate_index */
allocate_size = 11 + 8 + 22 + 10 + index_len * 18;
GST_DEBUG_OBJECT (mux, "Allocating %d bytes for index", allocate_size);
index = gst_buffer_new_and_alloc (allocate_size);
data = GST_BUFFER_DATA (index);
GST_WRITE_UINT16_BE (data, 9); /* the 'keyframes' key */
memcpy (data + 2, "keyframes", 9);
GST_WRITE_UINT8 (data + 11, 8); /* nested ECMA array */
GST_WRITE_UINT32_BE (data + 12, 2); /* two elements */
GST_WRITE_UINT16_BE (data + 16, 5); /* first string key: 'times' */
memcpy (data + 18, "times", 5);
GST_WRITE_UINT8 (data + 23, 10); /* strict array */
GST_WRITE_UINT32_BE (data + 24, index_len);
data += 28;
/* the keyframes' times */
for (i = 0, l = mux->index; l; l = l->next, i++) {
GstFlvMuxIndexEntry *entry = l->data;
if (i % index_skip != 0)
continue;
data[0] = 0;
GST_WRITE_DOUBLE_BE (&data[1], entry->time);
GST_WRITE_UINT8 (data, 0); /* numeric (aka double) */
GST_WRITE_DOUBLE_BE (data + 1, entry->time);
data += 9;
}
script_tag = gst_buffer_join (script_tag, tmp);
tmp = gst_buffer_new_and_alloc (2 + 13 + 1 + 4 + index_len * (1 + 8));
data = GST_BUFFER_DATA (tmp);
data[0] = 0; /* 13 bytes name */
data[1] = 13;
memcpy (&data[2], "filepositions", 13);
data[15] = 10; /* array */
GST_WRITE_UINT32_BE (&data[16], index_len);
GST_WRITE_UINT16_BE (data, 13); /* second string key: 'filepositions' */
memcpy (data + 2, "filepositions", 13);
GST_WRITE_UINT8 (data + 15, 10); /* strict array */
GST_WRITE_UINT32_BE (data + 16, index_len);
data += 20;
/* the keyframes' file positions */
for (i = 0, l = mux->index; l; l = l->next, i++) {
GstFlvMuxIndexEntry *entry = l->data;
if (i % index_skip != 0)
continue;
data[0] = 0;
GST_WRITE_DOUBLE_BE (&data[1], entry->position);
GST_WRITE_UINT8 (data, 0);
GST_WRITE_DOUBLE_BE (data + 1, entry->position);
data += 9;
}
script_tag = gst_buffer_join (script_tag, tmp);
tmp = gst_buffer_new_and_alloc (3);
data = GST_BUFFER_DATA (tmp);
GST_WRITE_UINT24_BE (data, 9); /* finish the ECMA array */
script_tag = gst_buffer_join (script_tag, tmp);
tmp = gst_buffer_new_and_alloc (4);
data = GST_BUFFER_DATA (tmp);
GST_WRITE_UINT32_BE (data, GST_BUFFER_SIZE (script_tag));
script_tag = gst_buffer_join (script_tag, tmp);
/* If there is space left in the prefilled area, reinsert the filler.
There is at least 18 bytes free, so it will always fit. */
if (index_len < MAX_INDEX_ENTRIES) {
GstBuffer *tmp;
guint8 *data;
guint32 remaining_filler_size;
data = GST_BUFFER_DATA (script_tag);
data[1] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 16) & 0xff;
data[2] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 8) & 0xff;
data[3] = ((GST_BUFFER_SIZE (script_tag) - 11 - 4) >> 0) & 0xff;
tmp = gst_buffer_new_and_alloc (14);
data = GST_BUFFER_DATA (tmp);
GST_WRITE_UINT16_BE (data, 9);
memcpy (data + 2, "gstfiller", 9);
GST_WRITE_UINT8 (data + 11, 2); /* string */
gst_buffer_set_caps (script_tag, GST_PAD_CAPS (mux->srcpad));
ret = gst_flv_mux_push (mux, script_tag);
/* There is 18 bytes per remaining index entry minus what is used for
* the'gstfiller' key. The rest is already filled with spaces, so just need
* to update length. */
remaining_filler_size = (MAX_INDEX_ENTRIES - index_len) * 18 - 14;
GST_DEBUG_OBJECT (mux, "Remaining filler size is %d bytes",
remaining_filler_size);
GST_WRITE_UINT16_BE (data + 12, remaining_filler_size);
index = gst_buffer_join (index, tmp);
}
gst_buffer_set_caps (index, GST_PAD_CAPS (mux->srcpad));
ret = gst_flv_mux_push (mux, index);
return ret;
}