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 "config_components.h"
  23
  24 #include "libavutil/avstring.h"
  25 #include "libavutil/mem.h"
  26 #include "libavutil/opt.h"
  27
  28 #include "avio_internal.h"
  29 #include "avformat.h"
  30 #include "demux.h"
  31 #include "id3v2.h"
  32 #include "internal.h"
  33 #include "url.h"
  34
  35
  36 /**
  37  * @file
  38  * Format register and lookup
  39  */
  40
  41 int av_match_ext(const char *filename, const char *extensions)
  42 {
  43     const char *ext;
  44
  45     if (!filename)
  46         return 0;
  47
  48     ext = strrchr(filename, '.');
  49     if (ext)
  50         return av_match_name(ext + 1, extensions);
  51     return 0;
  52 }
  53
  54 int ff_match_url_ext(const char *url, const char *extensions)
  55 {
  56     const char *ext;
  57     URLComponents uc;
  58     int ret;
  59     char scratchpad[128];
  60
  61     if (!url)
  62         return 0;
  63
  64     ret = ff_url_decompose(&uc, url, NULL);
  65     if (ret < 0 || !URL_COMPONENT_HAVE(uc, scheme))
  66         return ret;
  67     for (ext = uc.query; *ext != '.' && ext > uc.path; ext--)
  68         ;
  69
  70     if (*ext != '.')
  71         return 0;
  72     if (uc.query - ext > sizeof(scratchpad))
  73         return AVERROR(ENOMEM); //not enough memory in our scratchpad
  74     av_strlcpy(scratchpad, ext + 1, uc.query - ext);
  75
  76     return av_match_name(scratchpad, extensions);
  77 }
  78
  79 const AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
  80                                       const char *mime_type)
  81 {
  82     const AVOutputFormat *fmt = NULL;
  83     const AVOutputFormat *fmt_found = NULL;
  84     void *i = 0;
  85     int score_max, score;
  86
  87     /* specific test for image sequences */
  88 #if CONFIG_IMAGE2_MUXER
  89     if (!short_name && filename &&
  90         av_filename_number_test(filename) &&
  91         ff_guess_image2_codec(filename) != AV_CODEC_ID_NONE) {
  92         return av_guess_format("image2", NULL, NULL);
  93     }
  94 #endif
  95     /* Find the proper file type. */
  96     score_max = 0;
  97     while ((fmt = av_muxer_iterate(&i))) {
  98         if (fmt->flags & AVFMT_EXPERIMENTAL && !short_name)
  99             continue;
 100         score = 0;
 101         if (fmt->name && short_name && av_match_name(short_name, fmt->name))
 102             score += 100;
 103         if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
 104             score += 10;
 105         if (filename && fmt->extensions &&
 106             av_match_ext(filename, fmt->extensions)) {
 107             score += 5;
 108         }
 109         if (score > score_max) {
 110             score_max = score;
 111             fmt_found = fmt;
 112         }
 113     }
 114     return fmt_found;
 115 }
 116
 117 enum AVCodecID av_guess_codec(const AVOutputFormat *fmt, const char *short_name,
 118                               const char *filename, const char *mime_type,
 119                               enum AVMediaType type)
 120 {
 121     if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
 122         const AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
 123         if (fmt2)
 124             fmt = fmt2;
 125     }
 126
 127     if (type == AVMEDIA_TYPE_VIDEO) {
 128         enum AVCodecID codec_id = AV_CODEC_ID_NONE;
 129
 130 #if CONFIG_IMAGE2_MUXER || CONFIG_IMAGE2PIPE_MUXER
 131         if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
 132             codec_id = ff_guess_image2_codec(filename);
 133         }
 134 #endif
 135         if (codec_id == AV_CODEC_ID_NONE)
 136             codec_id = fmt->video_codec;
 137         return codec_id;
 138     } else if (type == AVMEDIA_TYPE_AUDIO)
 139         return fmt->audio_codec;
 140     else if (type == AVMEDIA_TYPE_SUBTITLE)
 141         return fmt->subtitle_codec;
 142     else
 143         return AV_CODEC_ID_NONE;
 144 }
 145
 146 const AVInputFormat *av_find_input_format(const char *short_name)
 147 {
 148     const AVInputFormat *fmt = NULL;
 149     void *i = 0;
 150     while ((fmt = av_demuxer_iterate(&i)))
 151         if (av_match_name(short_name, fmt->name))
 152             return fmt;
 153     return NULL;
 154 }
 155
 156 const AVInputFormat *av_probe_input_format3(const AVProbeData *pd,
 157                                             int is_opened, int *score_ret)
 158 {
 159     AVProbeData lpd = *pd;
 160     const AVInputFormat *fmt1 = NULL;
 161     const AVInputFormat *fmt = NULL;
 162     int score, score_max = 0;
 163     void *i = 0;
 164     const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
 165     enum nodat {
 166         NO_ID3,
 167         ID3_ALMOST_GREATER_PROBE,
 168         ID3_GREATER_PROBE,
 169         ID3_GREATER_MAX_PROBE,
 170     } nodat = NO_ID3;
 171
 172     if (!lpd.buf)
 173         lpd.buf = (unsigned char *) zerobuffer;
 174
 175     if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
 176         int id3len = ff_id3v2_tag_len(lpd.buf);
 177         if (lpd.buf_size > id3len + 16) {
 178             if (lpd.buf_size < 2LL*id3len + 16)
 179                 nodat = ID3_ALMOST_GREATER_PROBE;
 180             lpd.buf      += id3len;
 181             lpd.buf_size -= id3len;
 182         } else if (id3len >= PROBE_BUF_MAX) {
 183             nodat = ID3_GREATER_MAX_PROBE;
 184         } else
 185             nodat = ID3_GREATER_PROBE;
 186     }
 187
 188     while ((fmt1 = av_demuxer_iterate(&i))) {
 189         if (fmt1->flags & AVFMT_EXPERIMENTAL)
 190             continue;
 191         if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
 192             continue;
 193         score = 0;
 194         if (ffifmt(fmt1)->read_probe) {
 195             score = ffifmt(fmt1)->read_probe(&lpd);
 196             if (score)
 197                 av_log(NULL, AV_LOG_TRACE, "Probing %s score:%d size:%d\n", fmt1->name, score, lpd.buf_size);
 198             if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
 199                 switch (nodat) {
 200                 case NO_ID3:
 201                     score = FFMAX(score, 1);
 202                     break;
 203                 case ID3_GREATER_PROBE:
 204                 case ID3_ALMOST_GREATER_PROBE:
 205                     score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
 206                     break;
 207                 case ID3_GREATER_MAX_PROBE:
 208                     score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
 209                     break;
 210                 }
 211             }
 212         } else if (fmt1->extensions) {
 213             if (av_match_ext(lpd.filename, fmt1->extensions))
 214                 score = AVPROBE_SCORE_EXTENSION;
 215         }
 216         if (av_match_name(lpd.mime_type, fmt1->mime_type)) {
 217             int old_score = score;
 218             score += AVPROBE_SCORE_MIME_BONUS;
 219             if (score > AVPROBE_SCORE_MAX) score = AVPROBE_SCORE_MAX;
 220             av_log(NULL, AV_LOG_DEBUG, "Probing %s score:%d increased to %d due to MIME type\n", fmt1->name, old_score, score);
 221         }
 222         if (score > score_max) {
 223             score_max = score;
 224             fmt       = fmt1;
 225         } else if (score == score_max)
 226             fmt = NULL;
 227     }
 228     if (nodat == ID3_GREATER_PROBE)
 229         score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
 230     *score_ret = score_max;
 231
 232     return fmt;
 233 }
 234
 235 const AVInputFormat *av_probe_input_format2(const AVProbeData *pd,
 236                                             int is_opened, int *score_max)
 237 {
 238     int score_ret;
 239     const AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
 240     if (score_ret > *score_max) {
 241         *score_max = score_ret;
 242         return fmt;
 243     } else
 244         return NULL;
 245 }
 246
 247 const AVInputFormat *av_probe_input_format(const AVProbeData *pd, int is_opened)
 248 {
 249     int score = 0;
 250     return av_probe_input_format2(pd, is_opened, &score);
 251 }
 252
 253 int av_probe_input_buffer2(AVIOContext *pb, const AVInputFormat **fmt,
 254                            const char *filename, void *logctx,
 255                            unsigned int offset, unsigned int max_probe_size)
 256 {
 257     AVProbeData pd = { filename ? filename : "" };
 258     uint8_t *buf = NULL;
 259     int ret = 0, probe_size, buf_offset = 0;
 260     int score = 0;
 261     int ret2;
 262     int eof = 0;
 263
 264     if (!max_probe_size)
 265         max_probe_size = PROBE_BUF_MAX;
 266     else if (max_probe_size < PROBE_BUF_MIN) {
 267         av_log(logctx, AV_LOG_ERROR,
 268                "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
 269         return AVERROR(EINVAL);
 270     }
 271
 272     if (offset >= max_probe_size)
 273         return AVERROR(EINVAL);
 274
 275     if (pb->av_class) {
 276         uint8_t *mime_type_opt = NULL;
 277         char *semi;
 278         av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
 279         pd.mime_type = (const char *)mime_type_opt;
 280         semi = pd.mime_type ? strchr(pd.mime_type, ';') : NULL;
 281         if (semi) {
 282             *semi = '\0';
 283         }
 284     }
 285
 286     for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt && !eof;
 287          probe_size = FFMIN(probe_size << 1,
 288                             FFMAX(max_probe_size, probe_size + 1))) {
 289         score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
 290
 291         /* Read probe data. */
 292         if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
 293             goto fail;
 294         if ((ret = avio_read(pb, buf + buf_offset,
 295                              probe_size - buf_offset)) < 0) {
 296             /* Fail if error was not end of file, otherwise, lower score. */
 297             if (ret != AVERROR_EOF)
 298                 goto fail;
 299
 300             score = 0;
 301             ret   = 0;          /* error was end of file, nothing read */
 302             eof   = 1;
 303         }
 304         buf_offset += ret;
 305         if (buf_offset < offset)
 306             continue;
 307         pd.buf_size = buf_offset - offset;
 308         pd.buf = &buf[offset];
 309
 310         memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
 311
 312         /* Guess file format. */
 313         *fmt = av_probe_input_format2(&pd, 1, &score);
 314         if (*fmt) {
 315             /* This can only be true in the last iteration. */
 316             if (score <= AVPROBE_SCORE_RETRY) {
 317                 av_log(logctx, AV_LOG_WARNING,
 318                        "Format %s detected only with low score of %d, "
 319                        "misdetection possible!\n", (*fmt)->name, score);
 320             } else
 321                 av_log(logctx, AV_LOG_DEBUG,
 322                        "Format %s probed with size=%d and score=%d\n",
 323                        (*fmt)->name, probe_size, score);
 324 #if 0
 325             FILE *f = fopen("probestat.tmp", "ab");
 326             fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
 327             fclose(f);
 328 #endif
 329         }
 330     }
 331
 332     if (!*fmt)
 333         ret = AVERROR_INVALIDDATA;
 334
 335 fail:
 336     /* Rewind. Reuse probe buffer to avoid seeking. */
 337     ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
 338     if (ret >= 0)
 339         ret = ret2;
 340
 341     av_freep(&pd.mime_type);
 342     return ret < 0 ? ret : score;
 343 }
 344
 345 int av_probe_input_buffer(AVIOContext *pb, const AVInputFormat **fmt,
 346                           const char *filename, void *logctx,
 347                           unsigned int offset, unsigned int max_probe_size)
 348 {
 349     int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
 350     return ret < 0 ? ret : 0;
 351 }