[FFmpeg-devel] [PATCH] avformat/hlsenc: add option hls_out_list_size

[Aman Gupta]

On Tue, Apr 10, 2018 at 9:49 AM, Bodecs Bela <bodecsb at vivanet.hu> wrote:

>
>
> 2018.04.10. 17:41 keltezéssel, Aman Gupta írta:
>
>> On Tue, Apr 10, 2018 at 1:28 AM, Steven Liu <lq at chinaffmpeg.org> wrote:
>>
>> when use hls_list_size and hls_flags delete_segments, there will saving
>>> hls_list_size * 2 +- segments, so this option can control the segments
>>> numbers.
>>>
>>> fix ticket: #7131
>>>
>>> Signed-off-by: Steven Liu <lq at chinaffmpeg.org>
>>> ---
>>>   doc/muxers.texi      |  4 ++++
>>>   libavformat/hlsenc.c | 13 +++++++++++++
>>>   2 files changed, 17 insertions(+)
>>>
>>> diff --git a/doc/muxers.texi b/doc/muxers.texi
>>> index cb75c261c5..21ef786bcf 100644
>>> --- a/doc/muxers.texi
>>> +++ b/doc/muxers.texi
>>> @@ -513,6 +513,10 @@ Segment will be cut on the next key frame after this
>>> time has passed.
>>>   Set the maximum number of playlist entries. If set to 0 the list file
>>>   will contain all the segments. Default value is 5.
>>>
>>> + at item hls_out_list_size @var{size}
>>> +Set the maximum number out of playlist entries. Default value is 1.
>>> +This option should be used with @code{hls_flags delete_segments}.
>>>
>>> I don't understand why a new option is required. Why can't the value of
>> hls_list_size be re-used?
>>
> as I understand this is a totally different option:
> nb_existing_segments = hls_list_size + hls_out_list_size
> currently:
> nb_existing_segments = hls_list_size + 1
>

According to #7131, the current behavior is to keep hls_list_size*2 + 1
segments on disk.


>
> I think this is a usefull new option. e.g. when network speed is very
> fluctuating and your client want to save all the segments.


I don't follow.. if the m3u8 only advertises the last hls_list_size
segments, then why does keeping the older ones help? How would the client
even know they exist?

Aman


>
>
>
>>
>> +
>>>   @item hls_ts_options @var{options_list}
>>>   Set output format options using a :-separated list of key=value
>>>   parameters. Values containing @code{:} special characters must be
>>> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
>>> index 2a54b4342e..ff4c88d798 100644
>>> --- a/libavformat/hlsenc.c
>>> +++ b/libavformat/hlsenc.c
>>> @@ -171,6 +171,7 @@ typedef struct HLSContext {
>>>       float time;            // Set by a private option.
>>>       float init_time;       // Set by a private option.
>>>       int max_nb_segments;   // Set by a private option.
>>> +    int hls_out_list_size; // Set by a private option.
>>>   #if FF_API_HLS_WRAP
>>>       int  wrap;             // Set by a private option.
>>>   #endif
>>> @@ -443,6 +444,7 @@ static int hls_delete_old_segments(AVFormatContext
>>> *s, HLSContext *hls,
>>>       HLSSegment *segment, *previous_segment = NULL;
>>>       float playlist_duration = 0.0f;
>>>       int ret = 0, path_size, sub_path_size;
>>> +    int segment_cnt = 0;
>>>       char *dirname = NULL, *p, *sub_path;
>>>       char *path = NULL;
>>>       AVDictionary *options = NULL;
>>> @@ -456,14 +458,24 @@ static int hls_delete_old_segments(AVFormatContext
>>> *s, HLSContext *hls,
>>>       }
>>>
>>>       segment = vs->old_segments;
>>> +    segment_cnt = 0;
>>>       while (segment) {
>>>           playlist_duration -= segment->duration;
>>>           previous_segment = segment;
>>>           segment = previous_segment->next;
>>> +        segment_cnt++;
>>>           if (playlist_duration <= -previous_segment->duration) {
>>>               previous_segment->next = NULL;
>>>               break;
>>>           }
>>> +
>>> +        if (!hls->hls_out_list_size) {
>>> +            av_log(s, AV_LOG_WARNING, "the hls_out_list_size value is 0,
>>> that's wrong, so turn it to default value 1.\n");
>>>
>>> If 0 is invalid value, it should be disallowed instead of showing a
>> warning.
>>
>>
>> +        }
>>> +        if (segment_cnt >= hls->hls_out_list_size) {
>>> +            previous_segment->next = NULL;
>>> +            break;
>>> +        }
>>>       }
>>>
>>>       if (segment && !hls->use_localtime_mkdir) {
>>> @@ -2779,6 +2791,7 @@ static const AVOption options[] = {
>>>       {"hls_time",      "set segment length in seconds",
>>>   OFFSET(time),    AV_OPT_TYPE_FLOAT,  {.dbl = 2},     0, FLT_MAX, E},
>>>       {"hls_init_time", "set segment length in seconds at init list",
>>>       OFFSET(init_time),    AV_OPT_TYPE_FLOAT,  {.dbl = 0},     0,
>>> FLT_MAX,
>>> E},
>>>       {"hls_list_size", "set maximum number of playlist entries",
>>> OFFSET(max_nb_segments),    AV_OPT_TYPE_INT,    {.i64 = 5},     0,
>>> INT_MAX,
>>> E},
>>> +    {"hls_out_list_size", "set maximum number of out to playlist
>>> entries",  OFFSET(hls_out_list_size),    AV_OPT_TYPE_INT,    {.i64 = 1},
>>>   0, INT_MAX, E},
>>>
>>> I think you can change this to 1, INT_MAX to disallow 0 values.
>>
>>
>>       {"hls_ts_options","set hls mpegts list of options for the container
>>> format used for hls", OFFSET(format_options_str), AV_OPT_TYPE_STRING,
>>> {.str
>>> = NULL},  0, 0,    E},
>>>       {"hls_vtt_options","set hls vtt list of options for the container
>>> format used for hls", OFFSET(vtt_format_options_str),
>>> AV_OPT_TYPE_STRING,
>>> {.str = NULL},  0, 0,    E},
>>>   #if FF_API_HLS_WRAP
>>> --
>>> 2.15.1
>>>
>>>
>>>
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