ffmpeg/libavformat/concatdec.c

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/*
* Copyright (c) 2012 Nicolas George
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/avstring.h"
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#include "libavutil/opt.h"
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#include "avformat.h"
#include "internal.h"
typedef struct {
char *url;
int64_t start_time;
int64_t duration;
} ConcatFile;
typedef struct {
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AVClass *class;
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ConcatFile *files;
ConcatFile *cur_file;
unsigned nb_files;
AVFormatContext *avf;
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int safe;
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} ConcatContext;
static int concat_probe(AVProbeData *probe)
{
return 0;
}
static char *get_keyword(uint8_t **cursor)
{
char *ret = *cursor += strspn(*cursor, SPACE_CHARS);
*cursor += strcspn(*cursor, SPACE_CHARS);
if (**cursor) {
*((*cursor)++) = 0;
*cursor += strspn(*cursor, SPACE_CHARS);
}
return ret;
}
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static int safe_filename(const char *f)
{
const char *start = f;
for (; *f; f++) {
/* A-Za-z0-9_- */
if (!((unsigned)((*f | 32) - 'a') < 26 ||
(unsigned)(*f - '0') < 10 || *f == '_' || *f == '-')) {
if (f == start)
return 0;
else if (*f == '/')
start = f + 1;
else if (*f != '.')
return 0;
}
}
return 1;
}
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#define FAIL(retcode) do { ret = (retcode); goto fail; } while(0)
static int add_file(AVFormatContext *avf, char *filename, ConcatFile **rfile,
unsigned *nb_files_alloc)
{
ConcatContext *cat = avf->priv_data;
ConcatFile *file;
char *url;
size_t url_len;
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if (cat->safe > 0 && !safe_filename(filename)) {
av_log(avf, AV_LOG_ERROR, "Unsafe file name '%s'\n", filename);
return AVERROR(EPERM);
}
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url_len = strlen(avf->filename) + strlen(filename) + 16;
if (!(url = av_malloc(url_len)))
return AVERROR(ENOMEM);
ff_make_absolute_url(url, url_len, avf->filename, filename);
av_free(filename);
if (cat->nb_files >= *nb_files_alloc) {
size_t n = FFMAX(*nb_files_alloc * 2, 16);
ConcatFile *new_files;
if (n <= cat->nb_files || n > SIZE_MAX / sizeof(*cat->files) ||
!(new_files = av_realloc(cat->files, n * sizeof(*cat->files))))
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return AVERROR(ENOMEM);
cat->files = new_files;
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*nb_files_alloc = n;
}
file = &cat->files[cat->nb_files++];
memset(file, 0, sizeof(*file));
*rfile = file;
file->url = url;
file->start_time = AV_NOPTS_VALUE;
file->duration = AV_NOPTS_VALUE;
return 0;
}
static int open_file(AVFormatContext *avf, unsigned fileno)
{
ConcatContext *cat = avf->priv_data;
ConcatFile *file = &cat->files[fileno];
int ret;
if ((ret = avformat_open_input(&cat->avf, file->url, NULL, NULL)) < 0 ||
(ret = avformat_find_stream_info(cat->avf, NULL)) < 0) {
av_log(avf, AV_LOG_ERROR, "Impossible to open '%s'\n", file->url);
return ret;
}
cat->cur_file = file;
if (file->start_time == AV_NOPTS_VALUE)
file->start_time = !fileno ? 0 :
cat->files[fileno - 1].start_time +
cat->files[fileno - 1].duration;
return 0;
}
static int concat_read_close(AVFormatContext *avf)
{
ConcatContext *cat = avf->priv_data;
unsigned i;
if (cat->avf)
avformat_close_input(&cat->avf);
for (i = 0; i < cat->nb_files; i++)
av_freep(&cat->files[i].url);
av_freep(&cat->files);
return 0;
}
static int concat_read_header(AVFormatContext *avf)
{
ConcatContext *cat = avf->priv_data;
uint8_t buf[4096];
uint8_t *cursor, *keyword;
int ret, line = 0, i;
unsigned nb_files_alloc = 0;
ConcatFile *file = NULL;
AVStream *st, *source_st;
while (1) {
if ((ret = ff_get_line(avf->pb, buf, sizeof(buf))) <= 0)
break;
line++;
cursor = buf;
keyword = get_keyword(&cursor);
if (!*keyword || *keyword == '#')
continue;
if (!strcmp(keyword, "file")) {
char *filename = av_get_token((const char **)&cursor, SPACE_CHARS);
if (!filename) {
av_log(avf, AV_LOG_ERROR, "Line %d: filename required\n", line);
FAIL(AVERROR_INVALIDDATA);
}
if ((ret = add_file(avf, filename, &file, &nb_files_alloc)) < 0)
FAIL(ret);
} else {
av_log(avf, AV_LOG_ERROR, "Line %d: unknown keyword '%s'\n",
line, keyword);
FAIL(AVERROR_INVALIDDATA);
}
}
if (ret < 0)
FAIL(ret);
if ((ret = open_file(avf, 0)) < 0)
FAIL(ret);
for (i = 0; i < cat->avf->nb_streams; i++) {
if (!(st = avformat_new_stream(avf, NULL)))
FAIL(AVERROR(ENOMEM));
source_st = cat->avf->streams[i];
if ((ret = avcodec_copy_context(st->codec, source_st->codec)) < 0)
FAIL(ret);
st->r_frame_rate = source_st->r_frame_rate;
st->avg_frame_rate = source_st->avg_frame_rate;
st->time_base = source_st->time_base;
st->sample_aspect_ratio = source_st->sample_aspect_ratio;
}
return 0;
fail:
concat_read_close(avf);
return ret;
}
static int open_next_file(AVFormatContext *avf)
{
ConcatContext *cat = avf->priv_data;
unsigned fileno = cat->cur_file - cat->files;
if (cat->cur_file->duration == AV_NOPTS_VALUE)
cat->cur_file->duration = cat->avf->duration;
if (++fileno >= cat->nb_files)
return AVERROR_EOF;
avformat_close_input(&cat->avf);
return open_file(avf, fileno);
}
static int concat_read_packet(AVFormatContext *avf, AVPacket *pkt)
{
ConcatContext *cat = avf->priv_data;
int ret;
int64_t delta;
while (1) {
if ((ret = av_read_frame(cat->avf, pkt)) != AVERROR_EOF ||
(ret = open_next_file(avf)) < 0)
break;
}
delta = av_rescale_q(cat->cur_file->start_time - cat->avf->start_time,
AV_TIME_BASE_Q,
cat->avf->streams[pkt->stream_index]->time_base);
if (pkt->pts != AV_NOPTS_VALUE)
pkt->pts += delta;
if (pkt->dts != AV_NOPTS_VALUE)
pkt->dts += delta;
return ret;
}
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#define OFFSET(x) offsetof(ConcatContext, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "safe", "enable safe mode",
OFFSET(safe), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, DEC },
{ NULL }
};
static const AVClass concat_class = {
.class_name = "concat demuxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
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AVInputFormat ff_concat_demuxer = {
.name = "concat",
.long_name = NULL_IF_CONFIG_SMALL("Virtual concatenation script"),
.priv_data_size = sizeof(ConcatContext),
.read_probe = concat_probe,
.read_header = concat_read_header,
.read_packet = concat_read_packet,
.read_close = concat_read_close,
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.priv_class = &concat_class,
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};