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-rw-r--r--demux/packet.c244
1 files changed, 244 insertions, 0 deletions
diff --git a/demux/packet.c b/demux/packet.c
new file mode 100644
index 0000000..ed43729
--- /dev/null
+++ b/demux/packet.c
@@ -0,0 +1,244 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include <libavcodec/avcodec.h>
+#include <libavutil/intreadwrite.h>
+
+#include "common/av_common.h"
+#include "common/common.h"
+#include "demux.h"
+
+#include "packet.h"
+
+// Free any refcounted data dp holds (but don't free dp itself). This does not
+// care about pointers that are _not_ refcounted (like demux_packet.codec).
+// Normally, a user should use talloc_free(dp). This function is only for
+// annoyingly specific obscure use cases.
+void demux_packet_unref_contents(struct demux_packet *dp)
+{
+ if (dp->avpacket) {
+ assert(!dp->is_cached);
+ av_packet_free(&dp->avpacket);
+ dp->buffer = NULL;
+ dp->len = 0;
+ }
+}
+
+static void packet_destroy(void *ptr)
+{
+ struct demux_packet *dp = ptr;
+ demux_packet_unref_contents(dp);
+}
+
+static struct demux_packet *packet_create(void)
+{
+ struct demux_packet *dp = talloc(NULL, struct demux_packet);
+ talloc_set_destructor(dp, packet_destroy);
+ *dp = (struct demux_packet) {
+ .pts = MP_NOPTS_VALUE,
+ .dts = MP_NOPTS_VALUE,
+ .duration = -1,
+ .pos = -1,
+ .start = MP_NOPTS_VALUE,
+ .end = MP_NOPTS_VALUE,
+ .stream = -1,
+ .avpacket = av_packet_alloc(),
+ };
+ MP_HANDLE_OOM(dp->avpacket);
+ return dp;
+}
+
+// This actually preserves only data and side data, not PTS/DTS/pos/etc.
+// It also allows avpkt->data==NULL with avpkt->size!=0 - the libavcodec API
+// does not allow it, but we do it to simplify new_demux_packet().
+struct demux_packet *new_demux_packet_from_avpacket(struct AVPacket *avpkt)
+{
+ if (avpkt->size > 1000000000)
+ return NULL;
+ struct demux_packet *dp = packet_create();
+ int r = -1;
+ if (avpkt->data) {
+ // We hope that this function won't need/access AVPacket input padding,
+ // because otherwise new_demux_packet_from() wouldn't work.
+ r = av_packet_ref(dp->avpacket, avpkt);
+ } else {
+ r = av_new_packet(dp->avpacket, avpkt->size);
+ }
+ if (r < 0) {
+ talloc_free(dp);
+ return NULL;
+ }
+ dp->buffer = dp->avpacket->data;
+ dp->len = dp->avpacket->size;
+ return dp;
+}
+
+// (buf must include proper padding)
+struct demux_packet *new_demux_packet_from_buf(struct AVBufferRef *buf)
+{
+ if (!buf)
+ return NULL;
+ if (buf->size > 1000000000)
+ return NULL;
+
+ struct demux_packet *dp = packet_create();
+ dp->avpacket->buf = av_buffer_ref(buf);
+ if (!dp->avpacket->buf) {
+ talloc_free(dp);
+ return NULL;
+ }
+ dp->avpacket->data = dp->buffer = buf->data;
+ dp->avpacket->size = dp->len = buf->size;
+ return dp;
+}
+
+// Input data doesn't need to be padded.
+struct demux_packet *new_demux_packet_from(void *data, size_t len)
+{
+ struct demux_packet *dp = new_demux_packet(len);
+ if (!dp)
+ return NULL;
+ memcpy(dp->avpacket->data, data, len);
+ return dp;
+}
+
+struct demux_packet *new_demux_packet(size_t len)
+{
+ if (len > INT_MAX)
+ return NULL;
+
+ struct demux_packet *dp = packet_create();
+ int r = av_new_packet(dp->avpacket, len);
+ if (r < 0) {
+ talloc_free(dp);
+ return NULL;
+ }
+ dp->buffer = dp->avpacket->data;
+ dp->len = len;
+ return dp;
+}
+
+void demux_packet_shorten(struct demux_packet *dp, size_t len)
+{
+ assert(len <= dp->len);
+ if (dp->len) {
+ dp->len = len;
+ memset(dp->buffer + dp->len, 0, AV_INPUT_BUFFER_PADDING_SIZE);
+ }
+}
+
+void free_demux_packet(struct demux_packet *dp)
+{
+ talloc_free(dp);
+}
+
+void demux_packet_copy_attribs(struct demux_packet *dst, struct demux_packet *src)
+{
+ dst->pts = src->pts;
+ dst->dts = src->dts;
+ dst->duration = src->duration;
+ dst->pos = src->pos;
+ dst->segmented = src->segmented;
+ dst->start = src->start;
+ dst->end = src->end;
+ dst->codec = src->codec;
+ dst->back_restart = src->back_restart;
+ dst->back_preroll = src->back_preroll;
+ dst->keyframe = src->keyframe;
+ dst->stream = src->stream;
+}
+
+struct demux_packet *demux_copy_packet(struct demux_packet *dp)
+{
+ struct demux_packet *new = NULL;
+ if (dp->avpacket) {
+ new = new_demux_packet_from_avpacket(dp->avpacket);
+ } else {
+ // Some packets might be not created by new_demux_packet*().
+ new = new_demux_packet_from(dp->buffer, dp->len);
+ }
+ if (!new)
+ return NULL;
+ demux_packet_copy_attribs(new, dp);
+ return new;
+}
+
+#define ROUND_ALLOC(s) MP_ALIGN_UP((s), 16)
+
+// Attempt to estimate the total memory consumption of the given packet.
+// This is important if we store thousands of packets and not to exceed
+// user-provided limits. Of course we can't know how much memory internal
+// fragmentation of the libc memory allocator will waste.
+// Note that this should return a "stable" value - e.g. if a new packet ref
+// is created, this should return the same value with the new ref. (This
+// implies the value is not exact and does not return the actual size of
+// memory wasted due to internal fragmentation.)
+size_t demux_packet_estimate_total_size(struct demux_packet *dp)
+{
+ size_t size = ROUND_ALLOC(sizeof(struct demux_packet));
+ size += 8 * sizeof(void *); // ta overhead
+ size += 10 * sizeof(void *); // additional estimate for ta_ext_header
+ if (dp->avpacket) {
+ assert(!dp->is_cached);
+ size += ROUND_ALLOC(dp->len);
+ size += ROUND_ALLOC(sizeof(AVPacket));
+ size += 8 * sizeof(void *); // ta overhead
+ size += ROUND_ALLOC(sizeof(AVBufferRef));
+ size += ROUND_ALLOC(64); // upper bound estimate on sizeof(AVBuffer)
+ size += ROUND_ALLOC(dp->avpacket->side_data_elems *
+ sizeof(dp->avpacket->side_data[0]));
+ for (int n = 0; n < dp->avpacket->side_data_elems; n++)
+ size += ROUND_ALLOC(dp->avpacket->side_data[n].size);
+ }
+ return size;
+}
+
+int demux_packet_set_padding(struct demux_packet *dp, int start, int end)
+{
+ if (!start && !end)
+ return 0;
+ if (!dp->avpacket)
+ return -1;
+ uint8_t *p = av_packet_new_side_data(dp->avpacket, AV_PKT_DATA_SKIP_SAMPLES, 10);
+ if (!p)
+ return -1;
+
+ AV_WL32(p + 0, start);
+ AV_WL32(p + 4, end);
+ return 0;
+}
+
+int demux_packet_add_blockadditional(struct demux_packet *dp, uint64_t id,
+ void *data, size_t size)
+{
+ if (!dp->avpacket)
+ return -1;
+ uint8_t *sd = av_packet_new_side_data(dp->avpacket,
+ AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL,
+ 8 + size);
+ if (!sd)
+ return -1;
+ AV_WB64(sd, id);
+ if (size > 0)
+ memcpy(sd + 8, data, size);
+ return 0;
+}
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