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asfdemux: fix performance issue, especially with high-bitrate streams

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Two things were suboptimal from a performance point of view:

a) consider a large media object such as a video keyframe, which
   may be split up into multiple fragments. We would assemble
   the media object as follows:
     buf = join (join (join (frag1, frag2), frag3), frag4)
   which causes many unnecessary memcpy()s, and malloc/free,
   which could easily add up to a multiple of the actual object
   size. To avoid this, we allocate a buffer of the size needed
   from the start and copy fragments into that directly.

b) for every fragment to join, we would create a sub-buffer
   before joining it (which would discard the sub-buffer again),
   leading to unnecessary miniobject create/free churn.

Conflicts:

	gst/asfdemux/asfpacket.c
	gst/asfdemux/asfpacket.h
This commit is contained in:
Tim-Philipp Müller 2012-04-12 13:56:48 +01:00 committed by Sebastian Dröge
parent 65436c8715
commit 3064bf4a86
2 changed files with 43 additions and 12 deletions
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51
gst/asfdemux/asfpacket.c
View file

@ -382,28 +382,58 @@ gst_asf_demux_parse_payload (GstASFDemux * demux, AsfPacket * packet,
GST_LOG_OBJECT (demux, "payload length: %u", payload_len);
if (payload_len > 0) {
if (payload_len == 0) {
GST_DEBUG_OBJECT (demux, "skipping empty payload");
} else if (payload.mo_offset == 0 && payload.mo_size == payload_len) {
/* if the media object is not fragmented, just create a sub-buffer */
GST_LOG_OBJECT (demux, "unfragmented media object size %u", payload_len);
payload.buf = asf_packet_create_payload_buffer (packet, p_data, p_size,
payload_len);
payload.buf_filled = payload_len;
gst_asf_payload_queue_for_stream (demux, &payload, stream);
} else {
const guint8 *payload_data = *p_data;
g_assert (payload_len <= *p_size);
*p_data += payload_len;
*p_size -= payload_len;
/* n-th fragment of a fragmented media object? */
if (payload.mo_offset != 0) {
AsfPayload *prev;
if ((prev = asf_payload_find_previous_fragment (&payload, stream))) {
if (payload.mo_offset != gst_buffer_get_size (prev->buf)) {
if (prev->buf == NULL || payload.mo_size != prev->mo_size ||
payload.mo_offset >= gst_buffer_get_size (prev->buf) ||
payload.mo_offset + payload_len >
gst_buffer_get_size (prev->buf)) {
GST_WARNING_OBJECT (demux, "Offset doesn't match previous data?!");
}
/* note: buffer join/merge might not preserve buffer flags */
prev->buf = gst_buffer_append (prev->buf, payload.buf);
GST_LOG_OBJECT (demux,
"Merged fragments, merged size: %" G_GSIZE_FORMAT,
gst_buffer_get_size (prev->buf));
} else {
gst_buffer_unref (payload.buf);
/* we assume fragments are payloaded with increasing mo_offset */
if (payload.mo_offset != prev->buf_filled) {
GST_WARNING_OBJECT (demux, "media object payload discontinuity: "
"offset=%u vs buf_filled=%u", payload.mo_offset,
prev->buf_filled);
}
gst_buffer_fill (prev->buf, payload.mo_offset,
payload_data, payload_len);
prev->buf_filled =
MAX (prev->buf_filled, payload.mo_offset + payload_len);
GST_LOG_OBJECT (demux, "Merged media object fragments, size now %u",
prev->buf_filled);
}
payload.buf = NULL;
} else {
GST_DEBUG_OBJECT (demux, "n-th payload fragment, but don't have "
"any previous fragment, ignoring payload");
}
} else {
GST_LOG_OBJECT (demux, "allocating buffer of size %u for fragmented "
"media object", payload.mo_size);
payload.buf = gst_buffer_new_allocate (NULL, payload.mo_size, NULL);
gst_buffer_fill (payload.buf, 0, payload_data, payload_len);
payload.buf_filled = payload_len;
gst_asf_payload_queue_for_stream (demux, &payload, stream);
}
}
@ -445,6 +475,7 @@ gst_asf_demux_parse_payload (GstASFDemux * demux, AsfPacket * packet,
if (G_LIKELY (sub_payload_len > 0)) {
payload.buf = asf_packet_create_payload_buffer (packet,
&payload_data, &payload_len, sub_payload_len);
payload.buf_filled = sub_payload_len;
payload.ts = ts;
if (G_LIKELY (ts_delta))

6
gst/asfdemux/asfpacket.h
View file

@ -32,6 +32,8 @@ typedef struct {
guint mo_number; /* media object number (unused) */
guint mo_offset; /* offset (timestamp for compressed data) */
guint mo_size; /* size of media-object-to-be, or 0 */
guint buf_filled; /* how much of the mo data we got so far */
GstBuffer *buf; /* buffer to assemble media-object or NULL*/
guint rep_data_len; /* should never be more than 256, since */
guint8 rep_data[256]; /* the length should be stored in a byte */
GstClockTime ts;
@ -41,7 +43,6 @@ typedef struct {
gboolean interlaced; /* default: FALSE */
gboolean tff;
gboolean rff;
GstBuffer *buf;
} AsfPayload;
typedef struct {
@ -58,9 +59,8 @@ typedef struct {
gboolean gst_asf_demux_parse_packet (GstASFDemux * demux, GstBuffer * buf);
/* FIXME - gst_buffer_get_size is slow */
#define gst_asf_payload_is_complete(payload) \
(gst_buffer_get_size ((payload)->buf) >= (payload)->mo_size)
((payload)->buf_filled >= (payload)->mo_size)
G_END_DECLS