HLS segmenting generates different EXT-X-TARGETDURATION values for different resolutions/framerates

[Lushi]

Summary of the bug:
I am trying to encode a video to HLS in multiple bitrates (and, therefore, according to apple's recommendations, multiple frame rates).

I can get one HLS working fine when I have a single variant. But when I have variants, I sometimes get different segment durations and, therefore, different TARGETDURATION (since they have different maxes). This means that the variants can't be used together.

For example, here are the first few lines of the m3u8 file of the same video encoded a 15 fps and 30 fps. Note the durations of the first segments have _different_lengths_. Also the TARGETDURATION is different.

    #EXT-X-TARGETDURATION:10
    #EXTINF:9.023222,
    480_0.ts

    #EXT-X-TARGETDURATION:10 
    #EXTINF:9.023222, 
    640_0.ts 

    #EXT-X-TARGETDURATION:9 
    #EXTINF:9.000000, 
    960_0.ts 

I have already posted to ffmpeg-users and discussed it on #ffmpeg irc.

Here are the links to a more complete writeup:
​http://ffmpeg-users.933282.n4.nabble.com/HLS-segment-duration-for-multiple-framerate-encoding-td4671498.html
​http://pastebin.com/JqxiMe3U

How to reproduce:
Source video file:​http://www.caminandes.com/download/01_llama_drama_1080p.zip
full logs with -v 9 -loglevel 99 are attached

ENCODING 1

%./ffmpeg   -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2 -acodec aac -r 15 -profile:v baseline -level 3 -b:v 1632k -maxrate 1746.24k -keyint_min 45 -g 45 -sc_threshold 0 -vf scale=480:-1 -hls_list_size 0 -hls_time 9 480_.m3u8
ffmpeg version N-48432-ga176bbc-static http://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.9.3 (Debian 4.9.3-1)
  configuration: --enable-gpl --enable-version3 --disable-shared --disable-debug --enable-runtime-cpudetect --enable-libmp3lame --enable-libx264 --enable-libx265 --enable-libwebp --enable-libspeex --enable-libvorbis --enable-libvpx --enable-libfreetype --enable-fontconfig --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-gray --enable-libopenjpeg --enable-libopus --enable-libass --enable-gnutls --enable-libvidstab --enable-libsoxr --cc=gcc-4.9
  libavutil      54. 28.100 / 54. 28.100
  libavcodec     56. 52.100 / 56. 52.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 27.100 /  5. 27.100
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '../infile.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2013-02-08 18:56:45
  Duration: 00:01:30.00, start: 0.000000, bitrate: 3120 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080, 2925 kb/s, 24 fps, 24 tbr, 48 tbn, 48 tbc (default)
    Metadata:
      creation_time   : 1970-01-01 00:00:00
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 191 kb/s (default)
    Metadata:
      creation_time   : 2013-02-08 18:56:46
      handler_name    : IsoMedia File Produced by Google, 5-11-2011
[libx264 @ 0x3a12de0] VBV maxrate specified, but no bufsize, ignored
[libx264 @ 0x3a12de0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x3a12de0] profile Constrained Baseline, level 3.0
Output #0, hls, to '480_.m3u8':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    encoder         : Lavf56.40.101
    Stream #0:0(und): Video: h264 (libx264), yuv420p, 480x270, q=-1--1, 1632 kb/s, 15 fps, 90k tbn, 15 tbc (default)
    Metadata:
      creation_time   : 1970-01-01 00:00:00
      handler_name    : VideoHandler
      encoder         : Lavc56.52.100 libx264
    Stream #0:1(und): Audio: aac, 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      creation_time   : 2013-02-08 18:56:46
      handler_name    : IsoMedia File Produced by Google, 5-11-2011
      encoder         : Lavc56.52.100 aac
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
frame= 1352 fps=123 q=-1.0 Lsize=N/A time=00:01:30.13 bitrate=N/A dup=0 drop=808    
video:16495kB audio:1394kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[libx264 @ 0x3a12de0] frame I:31    Avg QP: 3.48  size: 58339
[libx264 @ 0x3a12de0] frame P:1321  Avg QP: 5.84  size: 11418
[libx264 @ 0x3a12de0] mb I  I16..4: 31.5%  0.0% 68.5%
[libx264 @ 0x3a12de0] mb P  I16..4:  2.7%  0.0%  5.5%  P16..4: 45.3%  6.5%  8.2%  0.0%  0.0%    skip:31.8%
[libx264 @ 0x3a12de0] final ratefactor: 7.75
[libx264 @ 0x3a12de0] coded y,uvDC,uvAC intra: 86.8% 89.0% 88.6% inter: 45.3% 49.2% 47.7%
[libx264 @ 0x3a12de0] i16 v,h,dc,p: 34% 34% 18% 14%
[libx264 @ 0x3a12de0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 39% 12%  4%  5%  5%  8%  4%  7%
[libx264 @ 0x3a12de0] i8c dc,h,v,p: 46% 39%  8%  8%
[libx264 @ 0x3a12de0] ref P L0: 90.2%  6.3%  3.5%
[libx264 @ 0x3a12de0] kb/s:1499.21

ENCODING 2

%./ffmpeg   -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2 -acodec aac -r 30 -profile:v main -level 3.1 -b:v 1568k -maxrate 1677.76k -keyint_min 90 -g 90 -sc_threshold 0 -vf scale=960:-1 -hls_list_size 0 -hls_time 9 960_.m3u8
ffmpeg version N-48432-ga176bbc-static http://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.9.3 (Debian 4.9.3-1)
  configuration: --enable-gpl --enable-version3 --disable-shared --disable-debug --enable-runtime-cpudetect --enable-libmp3lame --enable-libx264 --enable-libx265 --enable-libwebp --enable-libspeex --enable-libvorbis --enable-libvpx --enable-libfreetype --enable-fontconfig --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-gray --enable-libopenjpeg --enable-libopus --enable-libass --enable-gnutls --enable-libvidstab --enable-libsoxr --cc=gcc-4.9
  libavutil      54. 28.100 / 54. 28.100
  libavcodec     56. 52.100 / 56. 52.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 27.100 /  5. 27.100
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '../infile.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2013-02-08 18:56:45
  Duration: 00:01:30.00, start: 0.000000, bitrate: 3120 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080, 2925 kb/s, 24 fps, 24 tbr, 48 tbn, 48 tbc (default)
    Metadata:
      creation_time   : 1970-01-01 00:00:00
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 191 kb/s (default)
    Metadata:
      creation_time   : 2013-02-08 18:56:46
      handler_name    : IsoMedia File Produced by Google, 5-11-2011
[libx264 @ 0x3350de0] VBV maxrate specified, but no bufsize, ignored
[libx264 @ 0x3350de0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x3350de0] profile Main, level 3.1
Output #0, hls, to '960_.m3u8':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    encoder         : Lavf56.40.101
    Stream #0:0(und): Video: h264 (libx264), yuv420p, 960x540, q=-1--1, 1568 kb/s, 30 fps, 90k tbn, 30 tbc (default)
    Metadata:
      creation_time   : 1970-01-01 00:00:00
      handler_name    : VideoHandler
      encoder         : Lavc56.52.100 libx264
    Stream #0:1(und): Audio: aac, 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      creation_time   : 2013-02-08 18:56:46
      handler_name    : IsoMedia File Produced by Google, 5-11-2011
      encoder         : Lavc56.52.100 aac
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
frame= 2700 fps=108 q=-1.0 Lsize=N/A time=00:01:30.00 bitrate=N/A dup=540 drop=0    
video:16105kB audio:1394kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[libx264 @ 0x3350de0] frame I:30    Avg QP:10.99  size: 99460
[libx264 @ 0x3350de0] frame P:974   Avg QP:13.39  size: 11549
[libx264 @ 0x3350de0] frame B:1696  Avg QP:17.09  size:  1332
[libx264 @ 0x3350de0] consecutive B-frames: 15.3%  2.1%  2.7% 80.0%
[libx264 @ 0x3350de0] mb I  I16..4: 29.2%  0.0% 70.8%
[libx264 @ 0x3350de0] mb P  I16..4:  5.9%  0.0%  6.1%  P16..4: 26.1%  8.0%  7.6%  0.0%  0.0%    skip:46.4%
[libx264 @ 0x3350de0] mb B  I16..4:  0.1%  0.0%  0.2%  B16..8: 16.1%  1.9%  0.7%  direct: 1.3%  skip:79.8%  L0:37.9% L1:56.3% BI: 5.8%
[libx264 @ 0x3350de0] final ratefactor: 15.30
[libx264 @ 0x3350de0] coded y,uvDC,uvAC intra: 52.5% 73.7% 39.7% inter: 7.3% 13.4% 1.9%
[libx264 @ 0x3350de0] i16 v,h,dc,p: 34% 38% 10% 18%
[libx264 @ 0x3350de0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 21% 32% 16%  4%  5%  5%  6%  4%  6%
[libx264 @ 0x3350de0] i8c dc,h,v,p: 50% 33% 13%  5%
[libx264 @ 0x3350de0] Weighted P-Frames: Y:12.8% UV:6.7%
[libx264 @ 0x3350de0] ref P L0: 72.2% 10.2% 12.0%  5.3%  0.3%
[libx264 @ 0x3350de0] ref B L0: 92.6%  6.1%  1.3%
[libx264 @ 0x3350de0] ref B L1: 95.1%  4.9%
[libx264 @ 0x3350de0] kb/s:1465.93

[Lushi]

./ffmpeg -v 9 -loglevel 99 output

[Lushi]

./ffmpeg -v 9 -loglevel 99 output

[Lushi]

m3u8 with TARGETDURATION:10

[Lushi]

m3u8 with TARGETDURATION:9

[Dennis E. Mungai]

Perhaps this bug is related to ​https://trac.ffmpeg.org/ticket/7073 ?

Only that in the ticket #7073, with variant streams, all other variant streams have the TARGETDURATION set to 0, whereas the first variant stream has the correct target duration set?