#6533: Invalid EXT-X-TARGETDURATION in HLS
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Reporter: tonn81 | Owner:
Type: defect | Status: reopened
Priority: normal | Component: avformat
Version: unspecified | Resolution:
Keywords: hls | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by tonn81):
OK, let me be more specific.
Specification says this rule must be followed:
`all {round(chunk_duration) <= EXT_X_TARGETDURATION}`
In current implementation, we have:
`EXT_X_TARGETDURATION = ceil(max{chunk_duration})`
It gives result that matches the specification (part about `less`) but
not precise.
I suggest to have:
`EXT_X_TARGETDURATION = round(max{chunk_duration})`
It gives result that matches the specification (part about `equal`)
and precise.
Also, that aligns with the value that user provided as input to ffmpeg
(`-hls_time`) and allows to ignore small difference that HLS segmenter
generates (e.g. `4.02` instead of `4.0`).
Current implementation:
{{{
for (en = hls->segments; en; en = en->next) {
if (target_duration <= en->duration)
# that would actually ceil
target_duration = get_int_from_double(en->duration);
}
}}}
Suggested implementation (pseudo-code):
{{{
for (en = hls->segments; en; en = en->next) {
if (target_duration < en->duration)
# if chunk duration is bigger than target duration -- round it
and use it,
# it could be also the same value as target_duration if
rounded to lower value
target_duration = round(en->duration);
}
}}}
--
Ticket URL: <https://trac.ffmpeg.org/ticket/6533#comment:12>
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