[FFmpeg-trac] #6533(avformat:reopened): Invalid EXT-X-TARGETDURATION in HLS

FFmpeg trac at avcodec.org
Fri Aug 16 11:04:33 EEST 2019


#6533: Invalid EXT-X-TARGETDURATION in HLS
-------------------------------------+------------------------------------
             Reporter:  tonn81       |                    Owner:
                 Type:  defect       |                   Status:  reopened
             Priority:  normal       |                Component:  avformat
              Version:  unspecified  |               Resolution:
             Keywords:  hls          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+------------------------------------
Changes (by thecodeassassin):

 * status:  closed => reopened
 * resolution:  wontfix =>


Comment:

 According to the spec:
    The EXT-X-TARGETDURATION tag specifies the maximum Media Segment
    duration.  The EXTINF duration of each Media Segment in the Playlist
    file, when rounded to the nearest integer, MUST be less than or equal
    to the target duration; longer segments can trigger playback stalls
    or other errors.  It applies to the entire Playlist file.  Its format
    is:

    #EXT-X-TARGETDURATION:<s>

 https://tools.ietf.org/html/rfc8216#section-4.3.3.1


 The way that the rounding is being done is invalid:
 https://github.com/FFmpeg/FFmpeg/blob/23678462c0a316772d112ca363a4ffdf7d4b4236/libavformat/hlsenc.c#L1482

 It results in invalid playlists:

 #EXTM3U
 #EXT-X-VERSION:3
 #EXT-X-TARGETDURATION:8
 #EXT-X-MEDIA-SEQUENCE:0
 #EXTINF:8.250000,
 0000.ts
 #EXTINF:7.227000,
 0001.ts
 #EXT-X-ENDLIST


 This playlist (while playable in ffplay, but not in most browser-based
 players) is invalid according to the specification.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6533#comment:25>
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