[FFmpeg-trac] #2224(avformat:closed): HLS output using b-frames has crazy initial timestamps

[FFmpeg]

#2224: HLS output using b-frames has crazy initial timestamps
-------------------------------------+-------------------------------------
             Reporter:  nealzebub    |                    Owner:
                 Type:  enhancement  |                   Status:  closed
             Priority:  normal       |                Component:  avformat
              Version:  unspecified  |               Resolution:  fixed
             Keywords:  libx264      |               Blocked By:
  mpegts hls segment                 |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  1            |
-------------------------------------+-------------------------------------
Changes (by saste):

 * status:  new => closed
 * type:  defect => enhancement
 * component:  undetermined => avformat
 * keywords:  libx264 mpegts hls => libx264 mpegts hls segment
 * analyzed:  0 => 1
 * resolution:   => fixed


Comment:

 Replying to [comment:8 nealzebub]:
 > I do not know if Wowza output produces Warnings in Validator, but I
 suspect not, since that is why they implemented the 10-second timestamp
 offset in version 3.5+.  I also suspect that they offset by 10 seconds to
 avoid the following two mediastreamvalidator issues reported.
 >
 > 1. Error - due to a negative timestamps, which is interpreted as a
 really high value.  Validator reports decreasing timestamps.  If the the
 first PTS is zero, then the first DTS is probably less than zero.
 >
 > 2. Warning - Validator, for some reason, is unable to read frames with a
 timestamp of zero.
 >
 > To be clear, a stream produced by FFmpeg using -avoid_negative_ts 1 can
 produce #2, the warning.
 >
 > Looking at the Wowza forums, it reads that Wowza was resistant to
 setting the offset in February 2012.  Then, in November 2012, the builds
 have the offset by default.
 >
 > I re-quote the Wowza thread from Sept 2012:
 > "
 > Below is the comment from one of the staff at Apple @baleighsdad:
 >
 > However, I'm not sure where Wowza got commit
 19ea08a11a8ea31797b509bf66a06c2f9e463d60

 Should be addressed in:
 {{{
 Author: Stefano Sabatini <stefasab at gmail.com>
 Date:   Fri Jul 5 14:28:38 2013 +0200

     lavf/segment: add initial_offset option

     Should address trac ticket #2224.
 their information; I don't recommend using a 0 PTS in the first segment,
 and have said many times that this isn't a good idea. Our own tools using
 a starting PTS of the equivalent of 10 seconds, to avoid wrap."
 }}}

 This requires the explicit use of the -initial_offset option, this can't
 be made the default since segment is a generic segment, and adding by
 default an arbitrary offset seems wrong.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2224#comment:9>
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