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FFmpeg/libavformat/format.c

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/*
* Format register and lookup
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
*
* 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 "avformat.h"
#include "internal.h"
#include "libavutil/atomic.h"
#include "libavutil/avstring.h"
/**
* @file
* Format register and lookup
*/
/** head of registered input format linked list */
static AVInputFormat *first_iformat = NULL;
/** head of registered output format linked list */
static AVOutputFormat *first_oformat = NULL;
AVInputFormat *av_iformat_next(AVInputFormat *f)
{
if (f)
return f->next;
else
return first_iformat;
}
AVOutputFormat *av_oformat_next(AVOutputFormat *f)
{
if (f)
return f->next;
else
return first_oformat;
}
void av_register_input_format(AVInputFormat *format)
{
AVInputFormat **p = &first_iformat;
format->next = NULL;
while(avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
p = &(*p)->next;
}
void av_register_output_format(AVOutputFormat *format)
{
AVOutputFormat **p = &first_oformat;
format->next = NULL;
while(avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
p = &(*p)->next;
}
int av_match_ext(const char *filename, const char *extensions)
{
const char *ext, *p;
char ext1[32], *q;
if (!filename)
return 0;
ext = strrchr(filename, '.');
if (ext) {
ext++;
p = extensions;
for (;;) {
q = ext1;
while (*p != '\0' && *p != ',' && q - ext1 < sizeof(ext1) - 1)
*q++ = *p++;
*q = '\0';
if (!av_strcasecmp(ext1, ext))
return 1;
if (*p == '\0')
break;
p++;
}
}
return 0;
}
static int match_format(const char *name, const char *names)
{
const char *p;
int len, namelen;
if (!name || !names)
return 0;
namelen = strlen(name);
while ((p = strchr(names, ','))) {
len = FFMAX(p - names, namelen);
if (!av_strncasecmp(name, names, len))
return 1;
names = p + 1;
}
return !av_strcasecmp(name, names);
}
AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
const char *mime_type)
{
AVOutputFormat *fmt = NULL, *fmt_found;
int score_max, score;
/* specific test for image sequences */
#if CONFIG_IMAGE2_MUXER
if (!short_name && filename &&
av_filename_number_test(filename) &&
ff_guess_image2_codec(filename) != AV_CODEC_ID_NONE) {
return av_guess_format("image2", NULL, NULL);
}
#endif
/* Find the proper file type. */
fmt_found = NULL;
score_max = 0;
while ((fmt = av_oformat_next(fmt))) {
score = 0;
if (fmt->name && short_name && match_format(short_name, fmt->name))
score += 100;
if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
score += 10;
if (filename && fmt->extensions &&
av_match_ext(filename, fmt->extensions)) {
score += 5;
}
if (score > score_max) {
score_max = score;
fmt_found = fmt;
}
}
return fmt_found;
}
enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
const char *filename, const char *mime_type,
enum AVMediaType type)
{
if (!strcmp(fmt->name, "segment") || !strcmp(fmt->name, "ssegment")) {
fmt = av_guess_format(NULL, filename, NULL);
}
if (type == AVMEDIA_TYPE_VIDEO) {
enum AVCodecID codec_id = AV_CODEC_ID_NONE;
#if CONFIG_IMAGE2_MUXER
if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
codec_id = ff_guess_image2_codec(filename);
}
#endif
if (codec_id == AV_CODEC_ID_NONE)
codec_id = fmt->video_codec;
return codec_id;
} else if (type == AVMEDIA_TYPE_AUDIO)
return fmt->audio_codec;
else if (type == AVMEDIA_TYPE_SUBTITLE)
return fmt->subtitle_codec;
else
return AV_CODEC_ID_NONE;
}
AVInputFormat *av_find_input_format(const char *short_name)
{
AVInputFormat *fmt = NULL;
while ((fmt = av_iformat_next(fmt)))
if (match_format(short_name, fmt->name))
return fmt;
return NULL;
}