| /* |
| * MPEG-DASH ISO BMFF segmenter |
| * Copyright (c) 2014 Martin Storsjo |
| * |
| * 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 "config.h" |
| #if HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| |
| #include "libavutil/avassert.h" |
| #include "libavutil/avstring.h" |
| #include "libavutil/intreadwrite.h" |
| #include "libavutil/mathematics.h" |
| #include "libavutil/opt.h" |
| #include "libavutil/rational.h" |
| #include "libavutil/time_internal.h" |
| |
| #include "avc.h" |
| #include "avformat.h" |
| #include "avio_internal.h" |
| #include "internal.h" |
| #include "isom.h" |
| #include "os_support.h" |
| #include "url.h" |
| #include "dash.h" |
| |
| static DASHTmplId dash_read_tmpl_id(const char *identifier, char *format_tag, |
| size_t format_tag_size, const char **ptr) { |
| const char *next_ptr; |
| DASHTmplId id_type = DASH_TMPL_ID_UNDEFINED; |
| |
| if (av_strstart(identifier, "$$", &next_ptr)) { |
| id_type = DASH_TMPL_ID_ESCAPE; |
| *ptr = next_ptr; |
| } else if (av_strstart(identifier, "$RepresentationID$", &next_ptr)) { |
| id_type = DASH_TMPL_ID_REP_ID; |
| // default to basic format, as $RepresentationID$ identifiers |
| // are not allowed to have custom format-tags. |
| av_strlcpy(format_tag, "%d", format_tag_size); |
| *ptr = next_ptr; |
| } else { // the following identifiers may have an explicit format_tag |
| if (av_strstart(identifier, "$Number", &next_ptr)) |
| id_type = DASH_TMPL_ID_NUMBER; |
| else if (av_strstart(identifier, "$Bandwidth", &next_ptr)) |
| id_type = DASH_TMPL_ID_BANDWIDTH; |
| else if (av_strstart(identifier, "$Time", &next_ptr)) |
| id_type = DASH_TMPL_ID_TIME; |
| else |
| id_type = DASH_TMPL_ID_UNDEFINED; |
| |
| // next parse the dash format-tag and generate a c-string format tag |
| // (next_ptr now points at the first '%' at the beginning of the format-tag) |
| if (id_type != DASH_TMPL_ID_UNDEFINED) { |
| const char *number_format = (id_type == DASH_TMPL_ID_TIME) ? PRId64 : "d"; |
| if (next_ptr[0] == '$') { // no dash format-tag |
| snprintf(format_tag, format_tag_size, "%%%s", number_format); |
| *ptr = &next_ptr[1]; |
| } else { |
| const char *width_ptr; |
| // only tolerate single-digit width-field (i.e. up to 9-digit width) |
| if (av_strstart(next_ptr, "%0", &width_ptr) && |
| av_isdigit(width_ptr[0]) && |
| av_strstart(&width_ptr[1], "d$", &next_ptr)) { |
| // yes, we're using a format tag to build format_tag. |
| snprintf(format_tag, format_tag_size, "%s%c%s", "%0", width_ptr[0], number_format); |
| *ptr = next_ptr; |
| } else { |
| av_log(NULL, AV_LOG_WARNING, "Failed to parse format-tag beginning with %s. Expected either a " |
| "closing '$' character or a format-string like '%%0[width]d', " |
| "where width must be a single digit\n", next_ptr); |
| id_type = DASH_TMPL_ID_UNDEFINED; |
| } |
| } |
| } |
| } |
| return id_type; |
| } |
| |
| void ff_dash_fill_tmpl_params(char *dst, size_t buffer_size, |
| const char *template, int rep_id, |
| int number, int bit_rate, |
| int64_t time) { |
| int dst_pos = 0; |
| const char *t_cur = template; |
| while (dst_pos < buffer_size - 1 && *t_cur) { |
| char format_tag[7]; // May be "%d", "%0Xd", or "%0Xlld" (for $Time$), where X is in [0-9] |
| int n = 0; |
| DASHTmplId id_type; |
| const char *t_next = strchr(t_cur, '$'); // copy over everything up to the first '$' character |
| if (t_next) { |
| int num_copy_bytes = FFMIN(t_next - t_cur, buffer_size - dst_pos - 1); |
| av_strlcpy(&dst[dst_pos], t_cur, num_copy_bytes + 1); |
| // advance |
| dst_pos += num_copy_bytes; |
| t_cur = t_next; |
| } else { // no more DASH identifiers to substitute - just copy the rest over and break |
| av_strlcpy(&dst[dst_pos], t_cur, buffer_size - dst_pos); |
| break; |
| } |
| |
| if (dst_pos >= buffer_size - 1 || !*t_cur) |
| break; |
| |
| // t_cur is now pointing to a '$' character |
| id_type = dash_read_tmpl_id(t_cur, format_tag, sizeof(format_tag), &t_next); |
| switch (id_type) { |
| case DASH_TMPL_ID_ESCAPE: |
| av_strlcpy(&dst[dst_pos], "$", 2); |
| n = 1; |
| break; |
| case DASH_TMPL_ID_REP_ID: |
| n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, rep_id); |
| break; |
| case DASH_TMPL_ID_NUMBER: |
| n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, number); |
| break; |
| case DASH_TMPL_ID_BANDWIDTH: |
| n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, bit_rate); |
| break; |
| case DASH_TMPL_ID_TIME: |
| n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, time); |
| break; |
| case DASH_TMPL_ID_UNDEFINED: |
| // copy over one byte and advance |
| av_strlcpy(&dst[dst_pos], t_cur, 2); |
| n = 1; |
| t_next = &t_cur[1]; |
| break; |
| } |
| // t_next points just past the processed identifier |
| // n is the number of bytes that were attempted to be written to dst |
| // (may have failed to write all because buffer_size). |
| |
| // advance |
| dst_pos += FFMIN(n, buffer_size - dst_pos - 1); |
| t_cur = t_next; |
| } |
| } |
| |
| |