[FFmpeg-devel] [PATCH] Add init_program_date_time so start time can be specified

[epirat07 at gmail.com]

On 17 Oct 2023, at 17:51, Dave Johansen wrote:

> ---
>  doc/muxers.texi      | 3 +++
>  libavformat/hlsenc.c | 7 ++++++-
>  2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index f6071484ff..87c19a5cb9 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -1086,6 +1086,9 @@ seeking. This flag should be used with the @code{hls_time} option.
>  @item program_date_time
>  Generate @code{EXT-X-PROGRAM-DATE-TIME} tags.
>
> + at item init_program_date_time
> +Time to start program date time at.
> +
>  @item second_level_segment_index
>  Makes it possible to use segment indexes as %%d in hls_segment_filename expression
>  besides date/time values when strftime is on.
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index 4ef84c05c1..474322cc21 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -28,6 +28,8 @@
>  #include <unistd.h>
>  #endif
>
> +#include "float.h"
> +
>  #include "libavutil/avassert.h"
>  #include "libavutil/mathematics.h"
>  #include "libavutil/avstring.h"
> @@ -212,6 +214,8 @@ typedef struct HLSContext {
>      int64_t recording_time;
>      int64_t max_seg_size; // every segment file max size
>
> +    double init_program_date_time;
> +
>      char *baseurl;
>      char *vtt_format_options_str;
>      char *subtitle_filename;
> @@ -2867,7 +2871,7 @@ static int hls_init(AVFormatContext *s)
>      char *p = NULL;
>      int http_base_proto = ff_is_http_proto(s->url);
>      int fmp4_init_filename_len = strlen(hls->fmp4_init_filename) + 1;
> -    double initial_program_date_time = av_gettime() / 1000000.0;
> +    double initial_program_date_time = hls->init_program_date_time ? hls->init_program_date_time : av_gettime() / 1000000.0;
>
>      if (hls->use_localtime) {
>          pattern = get_default_pattern_localtime_fmt(s);
> @@ -3141,6 +3145,7 @@ static const AVOption options[] = {
>      {"split_by_time", "split the hls segment by time which user set by hls_time", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SPLIT_BY_TIME }, 0, UINT_MAX,   E, "flags"},
>      {"append_list", "append the new segments into old hls segment list", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_APPEND_LIST }, 0, UINT_MAX,   E, "flags"},
>      {"program_date_time", "add EXT-X-PROGRAM-DATE-TIME", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_PROGRAM_DATE_TIME }, 0, UINT_MAX,   E, "flags"},
> +    {"init_program_date_time", "Time to start program date time at", OFFSET(init_program_date_time), AV_OPT_TYPE_DOUBLE, {.dbl = 0 }, 0, DBL_MAX,   E},

This should probably not be mixed into the flags options list.

It seems odd to have the user provide a double here instead of a ISO 8601 datetime, which is what the spec requires / ends up in the playlist.
If you do not want to handle the datetime string parsing, at least it would be good to give a hint what exactly the double value is expected to be here.

However usability-wise I would prefer to accept a proper date/time here…

>      {"second_level_segment_index", "include segment index in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_INDEX }, 0, UINT_MAX,   E, "flags"},
>      {"second_level_segment_duration", "include segment duration in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_DURATION }, 0, UINT_MAX,   E, "flags"},
>      {"second_level_segment_size", "include segment size in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_SIZE }, 0, UINT_MAX,   E, "flags"},
> -- 
> 2.39.2 (Apple Git-143)
>
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