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

[Steven Liu]

ChenLiucheng <gnattuoc at me.com> 于2022年10月11日周二 20:14写道：
>
>
>
> On Oct 11, 2022, at 14:19, Steven Liu <lingjiujianke at gmail.com> wrote:
>
> Steven Liu <lingjiujianke at gmail.com> 于2022年10月11日周二 10:55写道：
>
>
> gnattu <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>
> ---
> 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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>
> 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.
Do you mean documents? If yes, you need modify the file
./doc/demuxers.texi and add the option description, you can reference
the "max_reload" option.