mirror of https://git.ffmpeg.org/ffmpeg.git
228 lines
5.8 KiB
C
228 lines
5.8 KiB
C
/*
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* Metadata demuxer
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* Copyright (c) 2010 Anton Khirnov
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/bprint.h"
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#include "libavutil/mathematics.h"
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#include "avformat.h"
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#include "ffmeta.h"
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#include "internal.h"
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#include "libavutil/dict.h"
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static int probe(const AVProbeData *p)
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{
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if(!memcmp(p->buf, ID_STRING, strlen(ID_STRING)))
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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static int64_t read_line_to_bprint_escaped(AVIOContext *s, AVBPrint *bp)
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{
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int len, end;
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int64_t read = 0;
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char tmp[1024];
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char c;
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char prev = ' ';
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do {
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len = 0;
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do {
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c = avio_r8(s);
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end = prev != '\\' && (c == '\r' || c == '\n' || c == '\0');
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if (!end)
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tmp[len++] = c;
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prev = c;
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} while (!end && len < sizeof(tmp));
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av_bprint_append_data(bp, tmp, len);
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read += len;
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} while (!end);
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if (c == '\r' && avio_r8(s) != '\n' && !avio_feof(s))
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avio_skip(s, -1);
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if (!c && s->error)
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return s->error;
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if (!c && !read && avio_feof(s))
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return AVERROR_EOF;
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return read;
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}
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static void get_bprint_line(AVIOContext *s, AVBPrint *bp)
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{
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do {
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av_bprint_clear(bp);
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read_line_to_bprint_escaped(s, bp);
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} while (!avio_feof(s) && (bp->str[0] == ';' || bp->str[0] == '#' || bp->str[0] == 0));
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}
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static void get_line(AVIOContext *s, uint8_t *buf, int size)
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{
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do {
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uint8_t c;
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int i = 0;
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while ((c = avio_r8(s))) {
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if (c == '\\') {
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if (i < size - 1)
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buf[i++] = c;
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c = avio_r8(s);
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} else if (c == '\n')
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break;
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if (i < size - 1)
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buf[i++] = c;
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}
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buf[i] = 0;
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} while (!avio_feof(s) && (buf[0] == ';' || buf[0] == '#' || buf[0] == 0));
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}
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static AVChapter *read_chapter(AVFormatContext *s)
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{
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uint8_t line[256];
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int64_t start, end;
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AVRational tb = {1, 1e9};
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int ret;
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get_line(s->pb, line, sizeof(line));
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if (sscanf(line, "TIMEBASE=%d/%d", &tb.num, &tb.den))
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get_line(s->pb, line, sizeof(line));
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ret = sscanf(line, "START=%"SCNd64, &start);
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if (ret <= 0) {
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av_log(s, AV_LOG_ERROR, "Expected chapter start timestamp, found %s.\n", line);
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start = (s->nb_chapters && s->chapters[s->nb_chapters - 1]->end != AV_NOPTS_VALUE) ?
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s->chapters[s->nb_chapters - 1]->end : 0;
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} else
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get_line(s->pb, line, sizeof(line));
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ret = sscanf(line, "END=%"SCNd64, &end);
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if (ret <= 0) {
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av_log(s, AV_LOG_ERROR, "Expected chapter end timestamp, found %s.\n", line);
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end = AV_NOPTS_VALUE;
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}
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return avpriv_new_chapter(s, s->nb_chapters, tb, start, end, NULL);
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}
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static uint8_t *unescape(const uint8_t *buf, int size)
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{
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uint8_t *ret = av_malloc(size + 1);
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uint8_t *p1 = ret;
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const uint8_t *p2 = buf;
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if (!ret)
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return NULL;
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while (p2 < buf + size) {
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if (*p2 == '\\')
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p2++;
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*p1++ = *p2++;
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}
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*p1 = 0;
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return ret;
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}
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static int read_tag(const uint8_t *line, AVDictionary **m)
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{
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uint8_t *key, *value;
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const uint8_t *p = line;
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/* find first not escaped '=' */
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while (1) {
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if (*p == '=')
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break;
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else if (*p == '\\')
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p++;
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if (*p++)
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continue;
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return 0;
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}
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if (!(key = unescape(line, p - line)))
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return AVERROR(ENOMEM);
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if (!(value = unescape(p + 1, strlen(p + 1)))) {
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av_free(key);
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return AVERROR(ENOMEM);
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}
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av_dict_set(m, key, value, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
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return 0;
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}
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static int read_header(AVFormatContext *s)
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{
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AVDictionary **m = &s->metadata;
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AVBPrint bp;
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av_bprint_init(&bp, 0, AV_BPRINT_SIZE_UNLIMITED);
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while(!avio_feof(s->pb)) {
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get_bprint_line(s->pb, &bp);
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if (!memcmp(bp.str, ID_STREAM, strlen(ID_STREAM))) {
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AVStream *st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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st->codecpar->codec_type = AVMEDIA_TYPE_DATA;
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st->codecpar->codec_id = AV_CODEC_ID_FFMETADATA;
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m = &st->metadata;
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} else if (!memcmp(bp.str, ID_CHAPTER, strlen(ID_CHAPTER))) {
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AVChapter *ch = read_chapter(s);
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if (!ch)
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return AVERROR(ENOMEM);
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m = &ch->metadata;
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} else
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read_tag(bp.str, m);
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}
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av_bprint_finalize(&bp, NULL);
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s->start_time = 0;
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if (s->nb_chapters)
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s->duration = av_rescale_q(s->chapters[s->nb_chapters - 1]->end,
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s->chapters[s->nb_chapters - 1]->time_base,
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AV_TIME_BASE_Q);
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return 0;
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}
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static int read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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return AVERROR_EOF;
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}
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AVInputFormat ff_ffmetadata_demuxer = {
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.name = "ffmetadata",
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.long_name = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text"),
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.read_probe = probe,
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.read_header = read_header,
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.read_packet = read_packet,
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};
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