[FFmpeg-devel] [PATCH] avformat/hls: Fixes #EXT-X-PROGRAM-DATE-TIME value of existing segments from getting over written with new value when appending new segments to an existing playlist file

[Vignesh Ravichandran]

Friendly reminder for review. Thank you.

Thanks,
Vignesh

On Sat, Nov 21, 2020 at 8:44 PM Vignesh Ravichandran <
vignesh.ravichandran02 at gmail.com> wrote:

> Signed-off-by: Vignesh Ravichandran <vignesh.ravichandran02 at gmail.com>
> ---
>  libavformat/hlsenc.c | 35 +++++++++++++++++++++++++++++++----
>  1 file changed, 31 insertions(+), 4 deletions(-)
>
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index cbfd8f7c0d..030a2d3b97 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -88,6 +88,7 @@ typedef struct HLSSegment {
>      char iv_string[KEYSIZE*2 + 1];
>
>      struct HLSSegment *next;
> +    double discont_program_date_time;
>  } HLSSegment;
>
>  typedef enum HLSFlags {
> @@ -1124,6 +1125,7 @@ static int hls_append_segment(struct AVFormatContext
> *s, HLSContext *hls,
>      en->keyframe_size     = vs->video_keyframe_size;
>      en->next     = NULL;
>      en->discont  = 0;
> +    en->discont_program_date_time = 0;
>
>      if (vs->discontinuity) {
>          en->discont = 1;
> @@ -1148,7 +1150,8 @@ static int hls_append_segment(struct AVFormatContext
> *s, HLSContext *hls,
>
>      if (hls->max_nb_segments && vs->nb_entries >= hls->max_nb_segments) {
>          en = vs->segments;
> -        vs->initial_prog_date_time += en->duration;
> +        if (!en->next->discont_program_date_time &&
> !en->discont_program_date_time)
> +            vs->initial_prog_date_time += en->duration;
>          vs->segments = en->next;
>          if (en && hls->flags & HLS_DELETE_SEGMENTS &&
>  #if FF_API_HLS_WRAP
> @@ -1182,6 +1185,8 @@ static int parse_playlist(AVFormatContext *s, const
> char *url, VariantStream *vs
>      char line[MAX_URL_SIZE];
>      const char *ptr;
>      const char *end;
> +    int is_discont_detected = 0;
> +    double discont_program_date_time = 0;
>
>      if ((ret = ffio_open_whitelist(&in, url, AVIO_FLAG_READ,
>                                     &s->interrupt_callback, NULL,
> @@ -1211,6 +1216,7 @@ static int parse_playlist(AVFormatContext *s, const
> char *url, VariantStream *vs
>          } else if (av_strstart(line, "#EXT-X-DISCONTINUITY", &ptr)) {
>              is_segment = 1;
>              vs->discontinuity = 1;
> +            is_discont_detected = 1;
>          } else if (av_strstart(line, "#EXTINF:", &ptr)) {
>              is_segment = 1;
>              vs->duration = atof(ptr);
> @@ -1236,7 +1242,23 @@ static int parse_playlist(AVFormatContext *s, const
> char *url, VariantStream *vs
>                      av_strlcpy(vs->iv_string, ptr, sizeof(vs->iv_string));
>                  }
>              }
> -
> +        } else if (av_strstart(line, "#EXT-X-PROGRAM-DATE-TIME:", &ptr)
> && is_discont_detected) {
> +            struct tm program_date_time;
> +            int y,M,d,h,m,s;
> +            double ms;
> +            sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h, &m, &s,
> &ms);
> +
> +            program_date_time.tm_year = y - 1900;
> +            program_date_time.tm_mon = M - 1;
> +            program_date_time.tm_mday = d;
> +            program_date_time.tm_hour = h;
> +            program_date_time.tm_min = m;
> +            program_date_time.tm_sec = s;
> +            program_date_time.tm_isdst = -1;
> +
> +            discont_program_date_time = mktime(&program_date_time);
> +            discont_program_date_time += (double)(ms / 1000);
> +            is_discont_detected = 0;
>          } else if (av_strstart(line, "#", NULL)) {
>              continue;
>          } else if (line[0]) {
> @@ -1250,8 +1272,9 @@ static int parse_playlist(AVFormatContext *s, const
> char *url, VariantStream *vs
>                  is_segment = 0;
>                  new_start_pos = avio_tell(vs->avf->pb);
>                  vs->size = new_start_pos - vs->start_pos;
> -                vs->initial_prog_date_time -= vs->duration; // this is a
> previously existing segment
>                  ret = hls_append_segment(s, hls, vs, vs->duration,
> vs->start_pos, vs->size);
> +                vs->last_segment->discont_program_date_time =
> discont_program_date_time;
> +                discont_program_date_time += vs->duration;
>                  if (ret < 0)
>                      goto fail;
>                  vs->start_pos = new_start_pos;
> @@ -1572,7 +1595,11 @@ static int hls_window(AVFormatContext *s, int last,
> VariantStream *vs)
>          ret = ff_hls_write_file_entry(byterange_mode ? hls->m3u8_out :
> vs->out, en->discont, byterange_mode,
>                                        en->duration, hls->flags &
> HLS_ROUND_DURATIONS,
>                                        en->size, en->pos, hls->baseurl,
> -                                      en->filename, prog_date_time_p,
> en->keyframe_size, en->keyframe_pos, hls->flags & HLS_I_FRAMES_ONLY);
> +                                      en->filename,
> +                                      en->discont_program_date_time ?
> &en->discont_program_date_time : prog_date_time_p,
> +                                      en->keyframe_size,
> en->keyframe_pos, hls->flags & HLS_I_FRAMES_ONLY);
> +        if (en->discont_program_date_time)
> +            en->discont_program_date_time -= en->duration;
>          if (ret < 0) {
>              av_log(s, AV_LOG_WARNING, "ff_hls_write_file_entry get
> error\n");
>          }
> --
> 2.24.2 (Apple Git-127)
>
>