[FFmpeg-devel] [PATCH] Wrong duration in TS container (Ticket #1836)

[Steven Liu]

2012/10/21 Heesuk Jung <heesuk.jung at lge.com>:
> Fix indentation.
>
> From 2723ad65908531d136b828e4c9e615104a12beb8 Mon Sep 17 00:00:00 2001
> From: Heesuk Jung <heesuk.jung at lge.com>
> Date: Sun, 21 Oct 2012 13:21:23 +0900
> Subject: [PATCH] Wrong duration in TS container (Ticket #1836)
>
> Libavformat somtimes get wrong duration in some TS conatiner.
> Please refer the problem description and file link in Ticket #1836.
> (http://ffmpeg.org/trac/ffmpeg/ticket/1836)
>
> I have just modified 2 point as below.
>
> 1. Duration determination considering time diff and file size / bit rate.
>
> Duration is determined base on PTS time diff (end time - start ime) but
> sometime is unreasonably so big.
> I suggest that don't beleive duration based on PTS time diff
> if time diff is bigger than hueristic value (file size / average bit rate *
> 2).
>
> 2. Change condition when estimate_timings_from_pts is called.
>
> The estimate_timings_from_pts function is designed for MPEG-PS.
> And so I changed condition from MPEG-TS to MPEG-PS
> ---
>  libavformat/utils.c |   32 +++++++++++++++++++++++++++++---
>  1 files changed, 29 insertions(+), 3 deletions(-)
>  mode change 100644 => 100755 libavformat/utils.c
>
> diff --git a/libavformat/utils.c b/libavformat/utils.c
> old mode 100644
> new mode 100755
> index 745dcaa..d322907
> --- a/libavformat/utils.c
> +++ b/libavformat/utils.c
> @@ -2035,6 +2035,29 @@ static int has_duration(AVFormatContext *ic)
>  }
>
>  /**
> + * examine if estimation from pts difference(end pts - start pts) is valid
> or not.
> + * determine invalid duration if pts difference is un reasonably bigger
> than file size/average bit rate.
> + * hueristically suggest  limit_filesize_multiple that means double file
> size
> + * @return 1 if time_diff (end_time - start_time) is valid.
> + *         0 if time_diff (end_time - start_time) is not valid.
> + */
> +static int valid_duration_from_pts(const int64_t start_time, const int64_t
> end_time,
> +                                    const int64_t filesize, int const
> bit_rate)
> +{
> +    const uint8_t limit_filesize_multiple = 2;
> +    const int64_t time_diff = end_time - start_time;
> +
> +    if (bit_rate != 0) {
> +        if (time_diff >
> (filesize*8/bit_rate*limit_filesize_multiple*1000000)) {
> +            return 0;
> +        }
> +        return 1;
> +    } else {
> +        return 0;
> +    }
> +}
> +
> +/**
>   * Estimate the stream timings from the one of each components.
>   *
>   * Also computes the global bitrate if possible.
> @@ -2077,8 +2100,11 @@ static void update_stream_timings(AVFormatContext
> *ic)
>
>      if (start_time != INT64_MAX) {
>          ic->start_time = start_time;
> -        if (end_time != INT64_MIN)
> -            duration = FFMAX(duration, end_time - start_time);
> +        if (end_time != INT64_MIN) {
> +            if (valid_duration_from_pts(start_time, end_time,
> avio_size(ic->pb), ic->bit_rate)) {
> +                duration = FFMAX(duration, end_time - start_time);
> +            }
> +        }
>      }
>      if (duration != INT64_MIN && duration > 0 && ic->duration ==
> AV_NOPTS_VALUE) {
>          ic->duration = duration;
> @@ -2233,7 +2259,7 @@ static void estimate_timings(AVFormatContext *ic,
> int64_t old_offset)
>      }
>
>      if ((!strcmp(ic->iformat->name, "mpeg") ||
> -         !strcmp(ic->iformat->name, "mpegts")) &&
> +         !strcmp(ic->iformat->name, "mpegps")) &&
>          file_size && ic->pb->seekable) {
>          /* get accurate estimate from the PTSes */
>          estimate_timings_from_pts(ic, old_offset);
> --
> 1.7.0.4
>
>
This patch is useful for me.

Thanks  Heesuk Jung