Function mergeSubtitleOverlaps

libhb/sync.c:2691–2797

Find all subtitles in the list that start "now" and overlap for some period of time. Create a new subtitle buffer that is the merged results of the overlapping parts and update start times of non-overlapping parts.

// merged results of the overlapping parts and update start times
// of non-overlapping parts.
static int mergeSubtitleOverlaps(subtitle_sanitizer_t *sanitizer)
{
    hb_buffer_t  * merged_buf   = NULL;
    hb_buffer_t  * a, * b;

    a = hb_buffer_list_head(&sanitizer->list_current);
    if (a != NULL && (a->s.flags & HB_BUF_FLAG_EOF))
    {
        // EOF
        return 0;
    }
    if (a == NULL ||
        a->s.start == AV_NOPTS_VALUE || a->s.stop == AV_NOPTS_VALUE)
    {
        // Not enough information to resolve an overlap
        return -1;
    }
    b = a->next;
    if (b != NULL && a->s.stop <= b->s.start)
    {
        // No overlap
        return 0;
    }

    // Check that we have 2 non-overlapping buffers in the list
    // and that all timestamps are valid up to the non-overlap.
    // This ensures that multiple overlapping subtitles have been
    // completely merged.
    while (b != NULL &&
           b->s.start < a->s.stop && !(b->s.flags & HB_BUF_FLAG_EOF))
    {
        if (b->s.start == AV_NOPTS_VALUE || b->s.stop == AV_NOPTS_VALUE)
        {
            // Not enough information to resolve an overlap
            return -1;
        }
        b = b->next;
    }
    if (b == NULL)
    {
        // Not enough information to resolve an overlap
        return -1;
    }

    hb_buffer_list_t   merged_list;
    int64_t            start, stop, last;

    if (b->s.flags & HB_BUF_FLAG_EOF)
    {
        last = INT64_MAX;
    }
    else
    {
        last = b->s.start;
    }

    hb_buffer_list_clear(&merged_list);
    a = hb_buffer_list_head(&sanitizer->list_current);