On Sat, May 29, 2021, 08:51 Pavel Koshevoy <pkoshe...@gmail.com> wrote:
> Un-hardcode the 200ms minimum latency between emitting subtitle events
> so that those that wish to receive a subtitle event for every screen
> change could do so.
>
> The problem with delaying realtime output by any amount is that it is
> unknown when the next byte pair that would trigger output will happen.
> It may be within 200ms, or it may be several seconds later -- that's
> not realtime at all.
> ---
> libavcodec/ccaption_dec.c | 4 +++-
> libavcodec/version.h | 2 +-
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
> index de05d037a8..27c61527f6 100644
> --- a/libavcodec/ccaption_dec.c
> +++ b/libavcodec/ccaption_dec.c
> @@ -238,6 +238,7 @@ struct Screen {
> typedef struct CCaptionSubContext {
> AVClass *class;
> int real_time;
> + int real_time_latency_msec;
> int data_field;
> struct Screen screen[2];
> int active_screen;
> @@ -906,7 +907,7 @@ static int decode(AVCodecContext *avctx, void *data,
> int *got_sub, AVPacket *avp
> }
>
> if (ctx->real_time && ctx->screen_touched &&
> - sub->pts > ctx->last_real_time + av_rescale_q(200, ms_tb,
> AV_TIME_BASE_Q)) {
> + sub->pts >= ctx->last_real_time +
> av_rescale_q(ctx->real_time_latency_msec, ms_tb, AV_TIME_BASE_Q)) {
> ctx->last_real_time = sub->pts;
> ctx->screen_touched = 0;
>
> @@ -927,6 +928,7 @@ static int decode(AVCodecContext *avctx, void *data,
> int *got_sub, AVPacket *avp
> #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
> static const AVOption options[] = {
> { "real_time", "emit subtitle events as they are decoded for
> real-time display", OFFSET(real_time), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0,
> 1, SD },
> + { "real_time_latency_msec", "minimum elapsed time between emitting
> real-time subtitle events", OFFSET(real_time_latency_msec),
> AV_OPT_TYPE_INT, { .i64 = 200 }, 0, 500, SD },
> { "data_field", "select data field", OFFSET(data_field),
> AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 1, SD, "data_field" },
> { "auto", "pick first one that appears", 0, AV_OPT_TYPE_CONST, {
> .i64 =-1 }, 0, 0, SD, "data_field" },
> { "first", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, 0, 0, SD,
> "data_field" },
> diff --git a/libavcodec/version.h b/libavcodec/version.h
> index 48165b9ac4..5b1e9e77f3 100644
> --- a/libavcodec/version.h
> +++ b/libavcodec/version.h
> @@ -29,7 +29,7 @@
>
> #define LIBAVCODEC_VERSION_MAJOR 59
> #define LIBAVCODEC_VERSION_MINOR 1
> -#define LIBAVCODEC_VERSION_MICRO 100
> +#define LIBAVCODEC_VERSION_MICRO 101
>
> #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
> LIBAVCODEC_VERSION_MINOR, \
> --
> 2.26.2
>
Are there any objections to this?
Thank you,
Pavel
>
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
