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libs/gst/base/gsttypefindhelper.c: Speedup typefinding. This is work in progress (see #459862).

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Original commit message from CVS:
* libs/gst/base/gsttypefindhelper.c:
Speedup typefinding. This is work in progress (see #459862).
This commit is contained in:
Stefan Kost 2007-10-03 12:05:17 +00:00
parent aeb491ef59
commit 4331d3880e
2 changed files with 43 additions and 6 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2007-10-03 Stefan Kost <ensonic@users.sf.net>
* libs/gst/base/gsttypefindhelper.c:
Speedup typefinding. This is work in progress (see #459862).
2007-10-03 Stefan Kost <ensonic@users.sf.net>
* gst/gstplugin.c:

44
libs/gst/base/gsttypefindhelper.c
View file

@ -58,6 +58,7 @@ typedef struct
{
GSList *buffers; /* buffer cache */
guint64 size;
guint64 last_offset;
GstTypeFindHelperGetRangeFunction func;
guint best_probability;
GstCaps *caps;
@ -71,7 +72,9 @@ typedef struct
* @off: stream offset
* @size: block size
*
* Get data pointer within a stream. Keeps a cache of read buffers.
* Get data pointer within a stream. Keeps a cache of read buffers (partly
* for performance reasons, but mostly because pointers returned by us need
* to stay valid until typefinding has finished)
*
* Returns: address of the data or %NULL if buffer does not cover the
* requested range.
@ -82,6 +85,7 @@ helper_find_peek (gpointer data, gint64 offset, guint size)
GstTypeFindHelper *helper;
GstBuffer *buffer;
GstFlowReturn ret;
GSList *insert_pos = NULL;
helper = (GstTypeFindHelper *) data;
@ -99,7 +103,7 @@ helper_find_peek (gpointer data, gint64 offset, guint size)
}
/* see if we have a matching buffer already in our list */
if (size > 0) {
if (size > 0 && offset <= helper->last_offset) {
GSList *walk;
for (walk = helper->buffers; walk; walk = walk->next) {
@ -107,13 +111,30 @@ helper_find_peek (gpointer data, gint64 offset, guint size)
guint64 buf_offset = GST_BUFFER_OFFSET (buf);
guint buf_size = GST_BUFFER_SIZE (buf);
if (buf_offset <= offset && (offset + size) < (buf_offset + buf_size))
return GST_BUFFER_DATA (buf) + (offset - buf_offset);
if (buf_offset <= offset) {
if ((offset + size) < (buf_offset + buf_size)) {
return GST_BUFFER_DATA (buf) + (offset - buf_offset);
}
/* buffers are kept sorted by offset (highest first) in the list, so
* at this point we know we don't need to check the remaining buffers
* (is that correct or just a guess that we're unlikely to find a
* match further down and it's most of the time not worth going through
* the entire list? How do we know the next buffer isn't offset-N with
* a big enough size to cover the requested offset+size?) */
insert_pos = walk;
break;
}
}
}
buffer = NULL;
ret = helper->func (helper->obj, offset, size, &buffer);
/* some typefinders go in 1 byte steps over 1k of data and request
* small buffers. It is really inefficient to pull each time, and pulling
* a larger chunk is almost free. Trying to pull a larger chunk at the end
* of the file is also not a problem here, we'll just get a truncated buffer
* in that case (and we'll have to double-check the size we actually get
* anyway, see below) */
ret = helper->func (helper->obj, offset, MAX (size, 512), &buffer);
if (ret != GST_FLOW_OK)
goto error;
@ -129,7 +150,17 @@ helper_find_peek (gpointer data, gint64 offset, guint size)
return NULL;
}
helper->buffers = g_slist_prepend (helper->buffers, buffer);
if (insert_pos) {
helper->buffers =
g_slist_insert_before (helper->buffers, insert_pos, buffer);
} else {
/* if insert_pos is not set, our offset is bigger than the largest offset
* we have so far; since we keep the list sorted with highest offsets
* first, we need to prepend the buffer to the list */
/* FIXME: why not last_offset = buffer_offset + buffer_size here? */
helper->last_offset = GST_BUFFER_OFFSET (buffer);
helper->buffers = g_slist_prepend (helper->buffers, buffer);
}
return GST_BUFFER_DATA (buffer);
error:
@ -214,6 +245,7 @@ gst_type_find_helper_get_range (GstObject * obj,
helper.buffers = NULL;
helper.size = size;
helper.last_offset = 0;
helper.func = func;
helper.best_probability = 0;
helper.caps = NULL;