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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 Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/avstring.h"
#include "libavutil/opt.h"
#include "avio_internal.h"
#include "avformat.h"
#include "id3v2.h"
#include "internal.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(const AVInputFormat *f)
{
if (f)
return f->next;
else
return first_iformat;
}
AVOutputFormat *av_oformat_next(const AVOutputFormat *f)
{
if (f)
return f->next;
else
return first_oformat;
}
void av_register_input_format(AVInputFormat *format)
{
AVInputFormat **p = &first_iformat;
while (*p)
p = &(*p)->next;
*p = format;
format->next = NULL;
}
void av_register_output_format(AVOutputFormat *format)
{
AVOutputFormat **p = &first_oformat;
while (*p)
p = &(*p)->next;
*p = format;
format->next = NULL;
}
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;
}
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 && !av_strcasecmp(fmt->name, short_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 (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 (av_match_name(short_name, fmt->name))
return fmt;
return NULL;
}
AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened,
int *score_max)
{
AVProbeData lpd = *pd;
AVInputFormat *fmt1 = NULL, *fmt;
int score, id3 = 0;
if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
int id3len = ff_id3v2_tag_len(lpd.buf);
if (lpd.buf_size > id3len + 16) {
lpd.buf += id3len;
lpd.buf_size -= id3len;
}
id3 = 1;
}
fmt = NULL;
while ((fmt1 = av_iformat_next(fmt1))) {
if (!is_opened == !(fmt1->flags & AVFMT_NOFILE))
continue;
score = 0;
if (fmt1->read_probe) {
score = fmt1->read_probe(&lpd);
} else if (fmt1->extensions) {
if (av_match_ext(lpd.filename, fmt1->extensions))
score = AVPROBE_SCORE_EXTENSION;
}
if (av_match_name(lpd.mime_type, fmt1->mime_type))
score = FFMAX(score, AVPROBE_SCORE_MIME);
if (score > *score_max) {
*score_max = score;
fmt = fmt1;
} else if (score == *score_max)
fmt = NULL;
}
// A hack for files with huge id3v2 tags -- try to guess by file extension.
if (!fmt && is_opened && *score_max < AVPROBE_SCORE_EXTENSION / 2) {
while ((fmt = av_iformat_next(fmt)))
if (fmt->extensions &&
av_match_ext(lpd.filename, fmt->extensions)) {
*score_max = AVPROBE_SCORE_EXTENSION / 2;
break;
}
}
if (!fmt && id3 && *score_max < AVPROBE_SCORE_EXTENSION / 2 - 1) {
while ((fmt = av_iformat_next(fmt)))
if (fmt->extensions && av_match_ext("mp3", fmt->extensions)) {
*score_max = AVPROBE_SCORE_EXTENSION / 2 - 1;
break;
}
}
return fmt;
}
AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened)
{
int score = 0;
return av_probe_input_format2(pd, is_opened, &score);
}
/* size of probe buffer, for guessing file type from file contents */
#define PROBE_BUF_MIN 2048
#define PROBE_BUF_MAX (1 << 20)
int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
const char *filename, void *logctx,
unsigned int offset, unsigned int max_probe_size)
{
AVProbeData pd = { filename ? filename : "" };
uint8_t *buf = NULL;
int ret = 0, probe_size;
uint8_t *mime_type_opt = NULL;
if (!max_probe_size)
max_probe_size = PROBE_BUF_MAX;
else if (max_probe_size > PROBE_BUF_MAX)
max_probe_size = PROBE_BUF_MAX;
else if (max_probe_size < PROBE_BUF_MIN)
return AVERROR(EINVAL);
if (offset >= max_probe_size)
return AVERROR(EINVAL);
avio_skip(pb, offset);
max_probe_size -= offset;
if (pb->av_class) {
av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
pd.mime_type = (const char *)mime_type_opt;
mime_type_opt = NULL;
}
for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;
probe_size = FFMIN(probe_size << 1,
FFMAX(max_probe_size, probe_size + 1))) {
int score = probe_size < max_probe_size ? AVPROBE_SCORE_MAX / 4 : 0;
/* Read probe data. */
if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
goto fail;
if ((ret = avio_read(pb, buf + pd.buf_size,
probe_size - pd.buf_size)) < 0) {
/* Fail if error was not end of file, otherwise, lower score. */
if (ret != AVERROR_EOF)
goto fail;
score = 0;
ret = 0; /* error was end of file, nothing read */
}
pd.buf_size += ret;
pd.buf = buf;
memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
/* Guess file format. */
*fmt = av_probe_input_format2(&pd, 1, &score);
if (*fmt) {
/* This can only be true in the last iteration. */
if (score <= AVPROBE_SCORE_MAX / 4) {
av_log(logctx, AV_LOG_WARNING,
"Format detected only with low score of %d, "
"misdetection possible!\n", score);
} else
av_log(logctx, AV_LOG_DEBUG,
"Probed with size=%d and score=%d\n", probe_size, score);
}
}
if (!*fmt)
ret = AVERROR_INVALIDDATA;
fail:
/* Rewind. Reuse probe buffer to avoid seeking. */
if (ret < 0 ||
(ret = ffio_rewind_with_probe_data(pb, buf, pd.buf_size)) < 0) {
av_free(buf);
}
av_freep(&pd.mime_type);
return ret;
}
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