[FFmpeg-devel] [PATCH v3] avformat/hls: Add option to retry failed segments for hls

[ChenLiucheng]

> On Oct 11, 2022, at 14:19, Steven Liu <lingjiujianke at gmail.com <mailto:lingjiujianke at gmail.com>> wrote:
> 
> Steven Liu <lingjiujianke at gmail.com <mailto:lingjiujianke at gmail.com>> 于2022年10月11日周二 10:55写道：
>> 
>> gnattu <gnattuoc at me.com <mailto:gnattuoc at me.com>> 于2022年10月10日周一 20:09写道：
>>> 
>>> Current HLS implementation simply skip a failed segment to catch up
>>> the stream, but this is not optimal for some use cases like livestream
>>> recording.
>>> Add an option to retry a failed segment to ensure the output file is
>>> a complete stream.
>>> 
>>> Signed-off-by: gnattu <gnattuoc at me.com <mailto:gnattuoc at me.com>>
>>> ---
>>> Fixed commit message wrap
>>> libavformat/hls.c | 15 ++++++++++++++-
>>> 1 file changed, 14 insertions(+), 1 deletion(-)
>>> 
>>> diff --git a/libavformat/hls.c b/libavformat/hls.c
>>> index e622425e80..2b977f9132 100644
>>> --- a/libavformat/hls.c
>>> +++ b/libavformat/hls.c
>>> @@ -225,6 +225,7 @@ typedef struct HLSContext {
>>>     int http_persistent;
>>>     int http_multiple;
>>>     int http_seekable;
>>> +    int seg_max_retry;
>>>     AVIOContext *playlist_pb;
>>>     HLSCryptoContext  crypto_ctx;
>>> } HLSContext;
>>> @@ -1472,6 +1473,7 @@ static int read_data(void *opaque, uint8_t *buf, int buf_size)
>>>     int ret;
>>>     int just_opened = 0;
>>>     int reload_count = 0;
>>> +    int segment_retries = 0;
>>>     struct segment *seg;
>>> 
>>> restart:
>>> @@ -1563,9 +1565,18 @@ reload:
>>>             av_log(v->parent, AV_LOG_WARNING, "Failed to open segment %"PRId64" of playlist %d\n",
>>>                    v->cur_seq_no,
>>>                    v->index);
>>> -            v->cur_seq_no += 1;
>>> +            if (segment_retries >= c->seg_max_retry) {
>>> +                av_log(v->parent, AV_LOG_WARNING, "Segment %"PRId64" of playlist %d failed too many times, skipping\n",
>>> +                       v->cur_seq_no,
>>> +                       v->index);
>>> +                v->cur_seq_no += 1;
>>> +                segment_retries = 0;
>>> +            } else {
>>> +                segment_retries += 1;
>>> +            }
>>>             goto reload;
>>>         }
>>> +        segment_retries = 0;
>>>         just_opened = 1;
>>>     }
>>> 
>>> @@ -2549,6 +2560,8 @@ static const AVOption hls_options[] = {
>>>         OFFSET(http_seekable), AV_OPT_TYPE_BOOL, { .i64 = -1}, -1, 1, FLAGS},
>>>     {"seg_format_options", "Set options for segment demuxer",
>>>         OFFSET(seg_format_opts), AV_OPT_TYPE_DICT, {.str = NULL}, 0, 0, FLAGS},
>>> +    {"seg_max_retry", "Maximum number of times to reload a segment on error.",
>>> +     OFFSET(seg_max_retry), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, FLAGS},
> BTW, Document should add describe about the option.
>>>     {NULL}
>>> };
>>> 
>>> --
>>> 2.37.0 (Apple Git-136)
>>> 
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>>> 
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>>> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
>> 
>> Not sure this functions is usefull. because there have a option named
>> "max_reload" for  playlist reload,
>> but this can be used for segment reload.
>> 
>> Perhaps there have some sence need reload segment, so this lookd ok to me.
> 
>> 
>> 
>> 
>> Thanks
>> Steven


May I have more clarification on this? Like on which aspect it need to have more details to better describe this option? I tried to keep the help text as concise as possible and I probably missed something here.