libavformat/format.c

   1 /*
   2  * Format register and lookup
   3  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/avstring.h"
  23 #include "libavutil/bprint.h"
  24 #include "libavutil/opt.h"
  25 #include "libavutil/thread.h"
  26
  27 #include "avio_internal.h"
  28 #include "avformat.h"
  29 #include "id3v2.h"
  30 #include "internal.h"
  31
  32
  33 /**
  34  * @file
  35  * Format register and lookup
  36  */
  37
  38 int av_match_ext(const char *filename, const char *extensions)
  39 {
  40     const char *ext;
  41
  42     if (!filename)
  43         return 0;
  44
  45     ext = strrchr(filename, '.');
  46     if (ext)
  47         return av_match_name(ext + 1, extensions);
  48     return 0;
  49 }
  50
  51 int ff_match_url_ext(const char *url, const char *extensions)
  52 {
  53     const char *ext;
  54     URLComponents uc;
  55     int ret;
  56     char scratchpad[128];
  57
  58     if (!url)
  59         return 0;
  60
  61     ret = ff_url_decompose(&uc, url, NULL);
  62     if (ret < 0 || !URL_COMPONENT_HAVE(uc, scheme))
  63         return ret;
  64     for (ext = uc.query; *ext != '.' && ext > uc.path; ext--)
  65         ;
  66
  67     if (*ext != '.')
  68         return 0;
  69     if (uc.query - ext > sizeof(scratchpad))
  70         return AVERROR(ENOMEM); //not enough memory in our scratchpad
  71     av_strlcpy(scratchpad, ext + 1, FFMIN(sizeof(scratchpad), uc.query - ext));
  72
  73     return av_match_name(scratchpad, extensions);
  74 }
  75
  76 ff_const59 AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
  77                                 const char *mime_type)
  78 {
  79     const AVOutputFormat *fmt = NULL;
  80     AVOutputFormat *fmt_found = NULL;
  81     void *i = 0;
  82     int score_max, score;
  83
  84     /* specific test for image sequences */
  85 #if CONFIG_IMAGE2_MUXER
  86     if (!short_name && filename &&
  87         av_filename_number_test(filename) &&
  88         ff_guess_image2_codec(filename) != AV_CODEC_ID_NONE) {
  89         return av_guess_format("image2", NULL, NULL);
  90     }
  91 #endif
  92     /* Find the proper file type. */
  93     score_max = 0;
  94     while ((fmt = av_muxer_iterate(&i))) {
  95         score = 0;
  96         if (fmt->name && short_name && av_match_name(short_name, fmt->name))
  97             score += 100;
  98         if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
  99             score += 10;
 100         if (filename && fmt->extensions &&
 101             av_match_ext(filename, fmt->extensions)) {
 102             score += 5;
 103         }
 104         if (score > score_max) {
 105             score_max = score;
 106             fmt_found = (AVOutputFormat*)fmt;
 107         }
 108     }
 109     return fmt_found;
 110 }
 111
 112 enum AVCodecID av_guess_codec(ff_const59 AVOutputFormat *fmt, const char *short_name,
 113                               const char *filename, const char *mime_type,
 114                               enum AVMediaType type)
 115 {
 116     if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
 117         ff_const59 AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
 118         if (fmt2)
 119             fmt = fmt2;
 120     }
 121
 122     if (type == AVMEDIA_TYPE_VIDEO) {
 123         enum AVCodecID codec_id = AV_CODEC_ID_NONE;
 124
 125 #if CONFIG_IMAGE2_MUXER
 126         if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
 127             codec_id = ff_guess_image2_codec(filename);
 128         }
 129 #endif
 130         if (codec_id == AV_CODEC_ID_NONE)
 131             codec_id = fmt->video_codec;
 132         return codec_id;
 133     } else if (type == AVMEDIA_TYPE_AUDIO)
 134         return fmt->audio_codec;
 135     else if (type == AVMEDIA_TYPE_SUBTITLE)
 136         return fmt->subtitle_codec;
 137     else if (type == AVMEDIA_TYPE_DATA)
 138         return fmt->data_codec;
 139     else
 140         return AV_CODEC_ID_NONE;
 141 }
 142
 143 ff_const59 AVInputFormat *av_find_input_format(const char *short_name)
 144 {
 145     const AVInputFormat *fmt = NULL;
 146     void *i = 0;
 147     while ((fmt = av_demuxer_iterate(&i)))
 148         if (av_match_name(short_name, fmt->name))
 149             return (AVInputFormat*)fmt;
 150     return NULL;
 151 }
 152
 153 ff_const59 AVInputFormat *av_probe_input_format3(ff_const59 AVProbeData *pd, int is_opened,
 154                                       int *score_ret)
 155 {
 156     AVProbeData lpd = *pd;
 157     const AVInputFormat *fmt1 = NULL;
 158     ff_const59 AVInputFormat *fmt = NULL;
 159     int score, score_max = 0;
 160     void *i = 0;
 161     const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
 162     enum nodat {
 163         NO_ID3,
 164         ID3_ALMOST_GREATER_PROBE,
 165         ID3_GREATER_PROBE,
 166         ID3_GREATER_MAX_PROBE,
 167     } nodat = NO_ID3;
 168
 169     if (!lpd.buf)
 170         lpd.buf = (unsigned char *) zerobuffer;
 171
 172     if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
 173         int id3len = ff_id3v2_tag_len(lpd.buf);
 174         if (lpd.buf_size > id3len + 16) {
 175             if (lpd.buf_size < 2LL*id3len + 16)
 176                 nodat = ID3_ALMOST_GREATER_PROBE;
 177             lpd.buf      += id3len;
 178             lpd.buf_size -= id3len;
 179         } else if (id3len >= PROBE_BUF_MAX) {
 180             nodat = ID3_GREATER_MAX_PROBE;
 181         } else
 182             nodat = ID3_GREATER_PROBE;
 183     }
 184
 185     while ((fmt1 = av_demuxer_iterate(&i))) {
 186         if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
 187             continue;
 188         score = 0;
 189         if (fmt1->read_probe) {
 190             score = fmt1->read_probe(&lpd);
 191             if (score)
 192                 av_log(NULL, AV_LOG_TRACE, "Probing %s score:%d size:%d\n", fmt1->name, score, lpd.buf_size);
 193             if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
 194                 switch (nodat) {
 195                 case NO_ID3:
 196                     score = FFMAX(score, 1);
 197                     break;
 198                 case ID3_GREATER_PROBE:
 199                 case ID3_ALMOST_GREATER_PROBE:
 200                     score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
 201                     break;
 202                 case ID3_GREATER_MAX_PROBE:
 203                     score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
 204                     break;
 205                 }
 206             }
 207         } else if (fmt1->extensions) {
 208             if (av_match_ext(lpd.filename, fmt1->extensions))
 209                 score = AVPROBE_SCORE_EXTENSION;
 210         }
 211         if (av_match_name(lpd.mime_type, fmt1->mime_type)) {
 212             if (AVPROBE_SCORE_MIME > score) {
 213                 av_log(NULL, AV_LOG_DEBUG, "Probing %s score:%d increased to %d due to MIME type\n", fmt1->name, score, AVPROBE_SCORE_MIME);
 214                 score = AVPROBE_SCORE_MIME;
 215             }
 216         }
 217         if (score > score_max) {
 218             score_max = score;
 219             fmt       = (AVInputFormat*)fmt1;
 220         } else if (score == score_max)
 221             fmt = NULL;
 222     }
 223     if (nodat == ID3_GREATER_PROBE)
 224         score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
 225     *score_ret = score_max;
 226
 227     return fmt;
 228 }
 229
 230 ff_const59 AVInputFormat *av_probe_input_format2(ff_const59 AVProbeData *pd, int is_opened, int *score_max)
 231 {
 232     int score_ret;
 233     ff_const59 AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
 234     if (score_ret > *score_max) {
 235         *score_max = score_ret;
 236         return fmt;
 237     } else
 238         return NULL;
 239 }
 240
 241 ff_const59 AVInputFormat *av_probe_input_format(ff_const59 AVProbeData *pd, int is_opened)
 242 {
 243     int score = 0;
 244     return av_probe_input_format2(pd, is_opened, &score);
 245 }
 246
 247 int av_probe_input_buffer2(AVIOContext *pb, ff_const59 AVInputFormat **fmt,
 248                           const char *filename, void *logctx,
 249                           unsigned int offset, unsigned int max_probe_size)
 250 {
 251     AVProbeData pd = { filename ? filename : "" };
 252     uint8_t *buf = NULL;
 253     int ret = 0, probe_size, buf_offset = 0;
 254     int score = 0;
 255     int ret2;
 256     int eof = 0;
 257
 258     if (!max_probe_size)
 259         max_probe_size = PROBE_BUF_MAX;
 260     else if (max_probe_size < PROBE_BUF_MIN) {
 261         av_log(logctx, AV_LOG_ERROR,
 262                "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
 263         return AVERROR(EINVAL);
 264     }
 265
 266     if (offset >= max_probe_size)
 267         return AVERROR(EINVAL);
 268
 269     if (pb->av_class) {
 270         uint8_t *mime_type_opt = NULL;
 271         char *semi;
 272         av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
 273         pd.mime_type = (const char *)mime_type_opt;
 274         semi = pd.mime_type ? strchr(pd.mime_type, ';') : NULL;
 275         if (semi) {
 276             *semi = '\0';
 277         }
 278     }
 279
 280     for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt && !eof;
 281          probe_size = FFMIN(probe_size << 1,
 282                             FFMAX(max_probe_size, probe_size + 1))) {
 283         score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
 284
 285         /* Read probe data. */
 286         if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
 287             goto fail;
 288         if ((ret = avio_read(pb, buf + buf_offset,
 289                              probe_size - buf_offset)) < 0) {
 290             /* Fail if error was not end of file, otherwise, lower score. */
 291             if (ret != AVERROR_EOF)
 292                 goto fail;
 293
 294             score = 0;
 295             ret   = 0;          /* error was end of file, nothing read */
 296             eof   = 1;
 297         }
 298         buf_offset += ret;
 299         if (buf_offset < offset)
 300             continue;
 301         pd.buf_size = buf_offset - offset;
 302         pd.buf = &buf[offset];
 303
 304         memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
 305
 306         /* Guess file format. */
 307         *fmt = av_probe_input_format2(&pd, 1, &score);
 308         if (*fmt) {
 309             /* This can only be true in the last iteration. */
 310             if (score <= AVPROBE_SCORE_RETRY) {
 311                 av_log(logctx, AV_LOG_WARNING,
 312                        "Format %s detected only with low score of %d, "
 313                        "misdetection possible!\n", (*fmt)->name, score);
 314             } else
 315                 av_log(logctx, AV_LOG_DEBUG,
 316                        "Format %s probed with size=%d and score=%d\n",
 317                        (*fmt)->name, probe_size, score);
 318 #if 0
 319             FILE *f = fopen("probestat.tmp", "ab");
 320             fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
 321             fclose(f);
 322 #endif
 323         }
 324     }
 325
 326     if (!*fmt)
 327         ret = AVERROR_INVALIDDATA;
 328
 329 fail:
 330     /* Rewind. Reuse probe buffer to avoid seeking. */
 331     ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
 332     if (ret >= 0)
 333         ret = ret2;
 334
 335     av_freep(&pd.mime_type);
 336     return ret < 0 ? ret : score;
 337 }
 338
 339 int av_probe_input_buffer(AVIOContext *pb, ff_const59 AVInputFormat **fmt,
 340                           const char *filename, void *logctx,
 341                           unsigned int offset, unsigned int max_probe_size)
 342 {
 343     int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
 344     return ret < 0 ? ret : 0;
 345 }