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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 "libavutil/atomic.h"
#include "libavutil/avstring.h"
#include "libavutil/bprint.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;
static AVInputFormat **last_iformat = &first_iformat;
static AVOutputFormat **last_oformat = &first_oformat;
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 = last_iformat;
format->next = NULL;
while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
p = &(*p)->next;
last_iformat = &format->next;
}
void av_register_output_format(AVOutputFormat *format)
{
AVOutputFormat **p = last_oformat;
format->next = NULL;
while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
p = &(*p)->next;
last_oformat = &format->next;
}
int av_match_ext(const char *filename, const char *extensions)
{
const char *ext;
if (!filename)
return 0;
ext = strrchr(filename, '.');
if (ext)
return av_match_name(ext + 1, extensions);
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_match_name(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 (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
if (fmt2)
fmt = fmt2;
}
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_format3(AVProbeData *pd, int is_opened,
int *score_ret)
{
AVProbeData lpd = *pd;
AVInputFormat *fmt1 = NULL, *fmt;
int score, nodat = 0, score_max = 0;
const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
if (!lpd.buf)
lpd.buf = zerobuffer;
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;
} else if (id3len >= PROBE_BUF_MAX) {
nodat = 2;
} else
nodat = 1;
}
fmt = NULL;
while ((fmt1 = av_iformat_next(fmt1))) {
if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
continue;
score = 0;
if (fmt1->read_probe) {
score = fmt1->read_probe(&lpd);
if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
if (nodat == 0) score = FFMAX(score, 1);
else if (nodat == 1) score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
else score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
}
} 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;
}
if (nodat == 1)
score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
*score_ret = score_max;
return fmt;
}
AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
{
int score_ret;
AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
if (score_ret > *score_max) {
*score_max = score_ret;
return fmt;
} else
return NULL;
}
AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened)
{
int score = 0;
return av_probe_input_format2(pd, is_opened, &score);
}
int av_probe_input_buffer2(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, buf_offset = 0;
int score = 0;
int ret2;
if (!max_probe_size)
max_probe_size = PROBE_BUF_MAX;
else if (max_probe_size < PROBE_BUF_MIN) {
av_log(logctx, AV_LOG_ERROR,
"Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
return AVERROR(EINVAL);
}
if (offset >= max_probe_size)
return AVERROR(EINVAL);
if (pb->av_class) {
uint8_t *mime_type_opt = NULL;
av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
pd.mime_type = (const char *)mime_type_opt;
}
#if 0
if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {
if (!av_strcasecmp(mime_type, "audio/aacp")) {
*fmt = av_find_input_format("aac");
}
av_freep(&mime_type);
}
#endif
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))) {
score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
/* Read probe data. */
if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
goto fail;
if ((ret = avio_read(pb, buf + buf_offset,
probe_size - buf_offset)) < 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 */
}
buf_offset += ret;
if (buf_offset < offset)
continue;
pd.buf_size = buf_offset - offset;
pd.buf = &buf[offset];
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_RETRY) {
av_log(logctx, AV_LOG_WARNING,
"Format %s detected only with low score of %d, "
"misdetection possible!\n", (*fmt)->name, score);
} else
av_log(logctx, AV_LOG_DEBUG,
"Format %s probed with size=%d and score=%d\n",
(*fmt)->name, probe_size, score);
#if 0
FILE *f = fopen("probestat.tmp", "ab");
fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
fclose(f);
#endif
}
}
if (!*fmt)
ret = AVERROR_INVALIDDATA;
fail:
/* Rewind. Reuse probe buffer to avoid seeking. */
ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
if (ret >= 0)
ret = ret2;
av_freep(&pd.mime_type);
return ret < 0 ? ret : score;
}
int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
const char *filename, void *logctx,
unsigned int offset, unsigned int max_probe_size)
{
int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
return ret < 0 ? ret : 0;
}
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