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976ee96e45
The size of all forward buffered packets is used to control maximum buffering. Until now, this size was incrementally adjusted, but had to be recomputed on seeks within the cache. Doing this was actually pretty expensive. It iterates over a linked list of separate memory allocations (which are probably spread all over the heap due to the allocation behavior), and the demux_packet_estimate_total_size() call touches a lot of further memory locations. I guess this affects the cache rather negatively. In an unscientific test, the recompute_buffers() function (which contained this loop) was responsible for roughly half of the time seeking took. Replace this with a way that computes the buffered size between 2 packets in constant times. The demux_packet.cum_pos field contains the summed sizes of all previous packets, so subtracting cum_pos between two packets yields the size of all packets in between. We can do this because we never remove packets from the middle of the queue. We only add packets to the end, or remove packets at the beginning. The tail_cum_pos field is needed because we don't store the end position of a packet, so the last packet's position would be unknown. We could recompute the "estimated" packet size, or store the estimated size in the packet struct, but I just didn't like this. This also removes the cached fw_bytes fields. It's slightly nicer to just recompute them when needed. Maintaining them incrementally was annoying. total_size stays though, since recomputing it isn't that cheap (would need to loop over all ranges every time). I'm always using uint64_t for sizes. This is certainly needed (a stream could easily burn through more than 4GB of data, even if much less of that is cached). The actual cached amount should always fit into size_t, so it's casted to size_t for printfs (yes, I hate the way you specify stdint.h types in printfs, the less I have to use that crap, the better).
74 lines
2.7 KiB
C
74 lines
2.7 KiB
C
/*
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* This file is part of mpv.
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*
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* mpv is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* mpv is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef MPLAYER_DEMUX_PACKET_H
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#define MPLAYER_DEMUX_PACKET_H
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#include <stdbool.h>
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#include <stddef.h>
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#include <inttypes.h>
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// Holds one packet/frame/whatever
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typedef struct demux_packet {
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double pts;
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double dts;
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double duration;
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int64_t pos; // position in source file byte stream
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unsigned char *buffer;
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int len;
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int stream; // source stream index (typically sh_stream.index)
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bool keyframe;
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// backward playback
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bool back_restart; // restart point (reverse and return previous frames)
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bool back_preroll; // initial discarded frame for smooth decoder reinit
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// segmentation (ordered chapters, EDL)
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bool segmented;
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struct mp_codec_params *codec; // set to non-NULL iff segmented is set
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double start, end; // set to non-NOPTS iff segmented is set
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// private
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struct demux_packet *next;
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struct AVPacket *avpacket; // keep the buffer allocation and sidedata
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uint64_t cum_pos; // demux.c internal: cumulative size until _start_ of pkt
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double kf_seek_pts; // demux.c internal: seek pts for keyframe range
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struct mp_packet_tags *metadata; // timed metadata (demux.c internal)
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} demux_packet_t;
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struct AVBufferRef;
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struct demux_packet *new_demux_packet(size_t len);
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struct demux_packet *new_demux_packet_from_avpacket(struct AVPacket *avpkt);
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struct demux_packet *new_demux_packet_from(void *data, size_t len);
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struct demux_packet *new_demux_packet_from_buf(struct AVBufferRef *buf);
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void demux_packet_shorten(struct demux_packet *dp, size_t len);
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void free_demux_packet(struct demux_packet *dp);
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struct demux_packet *demux_copy_packet(struct demux_packet *dp);
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size_t demux_packet_estimate_total_size(struct demux_packet *dp);
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void demux_packet_copy_attribs(struct demux_packet *dst, struct demux_packet *src);
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int demux_packet_set_padding(struct demux_packet *dp, int start, int end);
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int demux_packet_add_blockadditional(struct demux_packet *dp, uint64_t id,
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void *data, size_t size);
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#endif /* MPLAYER_DEMUX_PACKET_H */
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