[FFmpeg-trac] #7891(undetermined:new): Too many seek by media playback

FFmpeg trac at avcodec.org
Thu May 9 10:48:45 EEST 2019


#7891: Too many seek by media playback
-------------------------------------+-------------------------------------
             Reporter:               |                     Type:  defect
  Igor_Selivanov                     |
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:

 During media playback FFMPEG seeks in media format that causes TCP
 connection break. As result download speed is going down. In some cases
 download speed is slower than playback that cause playback interruption.

 This behavior is depended on media file format. Please find below TV
 recording from one of the Swiss HbbTV provider.

 Two files are available unter:

 https://cloud.loewe.de/index.php/s/Q3TGf73Jyqz5P10
 https://cloud.loewe.de/index.php/s/9QoEPe7lfsVTZjW

 How to reproduce:
 {{{
 ffplay -v verbose
 https://cloud.loewe.de/index.php/s/9QoEPe7lfsVTZjW/download
 }}}
 or
 {{{
 ffplay -v verbose -i
 https://cloud.loewe.de/index.php/s/Q3TGf73Jyqz5P10/download
 }}}

 Output shows periodically new TCP connections:
 {{{
 ....
 [tcp @ 0x7fc2dc8d47c0] Starting connection attempt to 10.12.20.175 port
 443
 [tcp @ 0x7fc2dc8d47c0] Successfully connected to 10.12.20.175 port 443
 ....
 }}}

 Playback as file (not over network) reports too many seeks. FFMPEG reports
 aprox. 100 seeks per second.

 {{{
 ffplay -v verbose da7b519f-f209-42a4-9de7-9c67b12b1059_P6.mp4
 }}}

 After 10 seconds playback
 {{{
 ....
 AVIOContext @ 0x7f5060009bc0] Statistics: 36594017 bytes read, 1025 seeks
 }}}


 Converting this file (with codec copy) fix "seek" problem:
 {{{
 ffmpeg -i da7b519f-f209-42a4-9de7-9c67b12b1059_P6.mp4 -c:v copy output.mp4
 }}}

 What is wrong in this format? Is it related to Wowza Media Server Pro
 transcoding approach? Can you please look at this.

 Thanks in advance

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7891>
FFmpeg <https://ffmpeg.org>
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