[FFmpeg-devel] [PATCH] fix typo in dashenc

[Gyan]

On 04-06-2019 06:29 PM, Alfred E. Heggestad wrote:
> On 04/06/2019 14:07, Gyan wrote:
>>
>>
>> On 04-06-2019 04:28 PM, Alfred E. Heggestad wrote:
>>> Hi Karthick,
>>>
>>> thanks for your feedback. here is an updated patch
>>> as you suggested.
>>>
>>>
>>>
>>>
>>>
>>>
>>> From 7879e39c25ede24693f166eb6a63094757d9fb1e Mon Sep 17 00:00:00 2001
>>> From: "Alfred E. Heggestad" <alfred.heggestad at gmail.com>
>>> Date: Tue, 4 Jun 2019 09:39:59 +0200
>>> Subject: [PATCH] dashenc: fix typo in seg_duration description
>>>
>>> doc: fix typo (seconds -> microseconds)
>>> ---
>>>  doc/muxers.texi       | 2 +-
>>>  libavformat/dashenc.c | 2 +-
>>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/doc/muxers.texi b/doc/muxers.texi
>>> index c73719c421..be02912b29 100644
>>> --- a/doc/muxers.texi
>>> +++ b/doc/muxers.texi
>>> @@ -232,7 +232,7 @@ ffmpeg -re -i <input> -map 0 -map 0 -c:a 
>>> libfdk_aac -c:v libx264
>>>  @item -min_seg_duration @var{microseconds}
>>>  This is a deprecated option to set the segment length in 
>>> microseconds, use @var{seg_duration} instead.
>>>  @item -seg_duration @var{duration}
>>> -Set the segment length in seconds (fractional value can be set). 
>>> The value is
>>> +Set the segment length in microseconds (fractional value can be 
>>> set). The value is
>>>  treated as average segment duration when @var{use_template} is 
>>> enabled and
>>>  @var{use_timeline} is disabled and as minimum segment duration for 
>>> all the other
>>>  use cases.
>>> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
>>> index 94b198ceb8..a70e9d176c 100644
>>> --- a/libavformat/dashenc.c
>>> +++ b/libavformat/dashenc.c
>>> @@ -1863,7 +1863,7 @@ static const AVOption options[] = {
>>>  #if FF_API_DASH_MIN_SEG_DURATION
>>>      { "min_seg_duration", "minimum segment duration (in 
>>> microseconds) (will be deprecated)", OFFSET(min_seg_duration), 
>>> AV_OPT_TYPE_INT, { .i64 = 5000000 }, 0, INT_MAX, E },
>>>  #endif
>>> -    { "seg_duration", "segment duration (in seconds, fractional 
>>> value can be set)", OFFSET(seg_duration), AV_OPT_TYPE_DURATION, { 
>>> .i64 = 5000000 }, 0, INT_MAX, E },
>>> +    { "seg_duration", "segment duration (in microseconds, 
>>> fractional value can be set)", OFFSET(seg_duration), 
>>> AV_OPT_TYPE_DURATION, { .i64 = 5000000 }, 0, INT_MAX, E },
>>>      { "remove_at_exit", "remove all segments when finished", 
>>> OFFSET(remove_at_exit), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, E },
>>>      { "use_template", "Use SegmentTemplate instead of SegmentList", 
>>> OFFSET(use_template), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, E },
>>>      { "use_timeline", "Use SegmentTimeline in SegmentTemplate", 
>>> OFFSET(use_timeline), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, E },
>>
>> This doesn't look right.
>>
>> I just tested ffmpeg cli with -seg_duration 4 and -seg_duration 
>> 4000000. The latter failed with "Value 4000000.000000 for parameter 
>> 'seg_duration' out of range [0 - 2147.48]" and the former produced 
>> segments of duration 4 seconds each.
>>
>> The field type is AV_OPT_TYPE_DURATION, and the avutil parser returns 
>> a microsecond value to the caller, but it expects the user string to 
>> be either HH:MM:SS or MM:SS or S+. Millisecond and microsecond values 
>> can be fed, with a suffix of ms or us, respectively.
>>
>
>
> this code is working for me:
>
>     ret |= av_opt_set_int(obj, "seg_duration",  10000000, 0);
>
>
>
> if you look in the declarations of options in dashenc.c:
>
> #if FF_API_DASH_MIN_SEG_DURATION
>     { "min_seg_duration", "minimum segment duration (in microseconds) 
> (will be deprecated)", OFFSET(min_seg_duration), AV_OPT_TYPE_INT, { 
> .i64 = 5000000 }, 0, INT_MAX, E },
> #endif
>     { "seg_duration", "segment duration (in seconds, fractional value 
> can be set)", OFFSET(seg_duration), AV_OPT_TYPE_DURATION, { .i64 = 
> 5000000 }, 0, INT_MAX, E },
>
>
> see the default value:
>
>     .i64 = 5000000

You should be using av_opt_set(), which will parse the value as per its 
type, which is AV_OPT_TYPE_DURATION and not AV_OPT_TYPE_INT. There is no 
specific setter for DURATION type.

Gyan