[FFmpeg-devel] [PATCH] avformat/hlsenc: add option hls_out_list_size
Aman Gupta
ffmpeg at tmm1.net
Tue Apr 10 20:41:06 EEST 2018
On Tue, Apr 10, 2018 at 10:36 AM, Bodecs Bela <bodecsb at vivanet.hu> wrote:
>
>
> 2018.04.10. 19:23 keltezéssel, Aman Gupta írta:
>
>> 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.
>>
> sorry, you are right.
>
>>
>> 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?
>>
> a currently joining client of course won't be aware about the earlier but
> still available segments,
> but a client, joinig eearlier and continouosly following m3u8 but
> temporarily having slower than realtime net connection speed
> may have benefit to successfully download these earlier segments.
>
Okay I understand now. You're right, this is a valid use-case. Thanks for
the clarification.
Aman
>
> it is not so usefull when realtime displaying the live stream, but it is
> usefull if you archive the live stream.
>
> bb
>
>
>
>> 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(AVForm
>>>>> atContext
>>>>> *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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>>>>> ffmpeg-devel at ffmpeg.org
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>>>>>
>>>>> _______________________________________________
>>>>>
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