mpv/stream/stream_concat.c

163 lines
4.3 KiB
C

/*
* 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 <libavutil/common.h>
#include "common/common.h"
#include "stream.h"
struct priv {
struct stream **streams;
int num_streams;
int64_t size;
int cur; // streams[cur] is the stream for current stream.pos
};
static int fill_buffer(struct stream *s, void *buffer, int len)
{
struct priv *p = s->priv;
while (1) {
int res = stream_read_partial(p->streams[p->cur], buffer, len);
if (res || p->cur == p->num_streams - 1)
return res;
p->cur += 1;
if (s->seekable)
stream_seek(p->streams[p->cur], 0);
}
}
static int seek(struct stream *s, int64_t newpos)
{
struct priv *p = s->priv;
int64_t next_pos = 0;
int64_t base_pos = 0;
// Look for the last stream whose start position is <= newpos.
// Note that the last stream's size is essentially ignored. The last
// stream is allowed to have an unknown size.
for (int n = 0; n < p->num_streams; n++) {
if (next_pos > newpos)
break;
base_pos = next_pos;
p->cur = n;
int64_t size = stream_get_size(p->streams[n]);
if (size < 0)
break;
next_pos = base_pos + size;
}
int ok = stream_seek(p->streams[p->cur], newpos - base_pos);
s->pos = base_pos + stream_tell(p->streams[p->cur]);
return ok;
}
static int64_t get_size(struct stream *s)
{
struct priv *p = s->priv;
return p->size;
}
static void s_close(struct stream *s)
{
struct priv *p = s->priv;
for (int n = 0; n < p->num_streams; n++)
free_stream(p->streams[n]);
}
static int open2(struct stream *stream, struct stream_open_args *args)
{
struct priv *p = talloc_zero(stream, struct priv);
stream->priv = p;
stream->fill_buffer = fill_buffer;
stream->get_size = get_size;
stream->close = s_close;
stream->seekable = true;
struct priv *list = args->special_arg;
if (!list || !list->num_streams) {
MP_FATAL(stream, "No sub-streams.\n");
return STREAM_ERROR;
}
for (int n = 0; n < list->num_streams; n++) {
struct stream *sub = list->streams[n];
int64_t size = stream_get_size(sub);
if (n != list->num_streams - 1 && size < 0) {
MP_WARN(stream, "Sub stream %d has unknown size.\n", n);
stream->seekable = false;
p->size = -1;
} else if (size >= 0 && p->size >= 0) {
p->size += size;
}
if (!sub->seekable)
stream->seekable = false;
MP_TARRAY_APPEND(p, p->streams, p->num_streams, sub);
}
if (stream->seekable)
stream->seek = seek;
return STREAM_OK;
}
static const stream_info_t stream_info_concat = {
.name = "concat",
.open2 = open2,
.protocols = (const char*const[]){ "concat", NULL },
};
// Create a stream with a concatenated view on streams[]. Copies the streams
// array. Takes over ownership of every stream passed to it (it will free them
// if the concat stream is closed).
// If an error happens, NULL is returned, and the streams are not freed.
struct stream *stream_concat_open(struct mpv_global *global, struct mp_cancel *c,
struct stream **streams, int num_streams)
{
// (struct priv is blatantly abused to pass in the stream list)
struct priv arg = {
.streams = streams,
.num_streams = num_streams,
};
struct stream_open_args sargs = {
.global = global,
.cancel = c,
.url = "concat://",
.flags = STREAM_READ | STREAM_SILENT,
.sinfo = &stream_info_concat,
.special_arg = &arg,
};
struct stream *s = NULL;
stream_create_with_args(&sargs, &s);
return s;
}