From 837580f458f2ccbbd6e82d3c7591916deb81ef02 Mon Sep 17 00:00:00 2001 From: Steven Liu Date: Fri, 1 Sep 2017 10:20:56 +0800 Subject: avformat/dash: move reused API to common file and header file move from dashenc, move DASHTmplId and dash_fill_tmpl_params to dash.c, they will be used by dash demuxer and dash muxer. v2 fixed: 1. rename common file from dashcomm.* to dash.* Suggested-by: Hendrik Leppkes v3 fixed: 1. rename header file pre defined 2. add ff_ prefix for the internal API Suggested-by: James Almer Suggested-by: Timo Rothenpieler Reviewed-by: wm4 Signed-off-by: Steven Liu --- libavformat/dash.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) create mode 100644 libavformat/dash.c (limited to 'libavformat/dash.c') diff --git a/libavformat/dash.c b/libavformat/dash.c new file mode 100644 index 0000000..b0b1ed4 --- /dev/null +++ b/libavformat/dash.c @@ -0,0 +1,136 @@ +#include "config.h" +#if HAVE_UNISTD_H +#include +#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; + } +} + + -- cgit v1.1