[FFmpeg-trac] #6868(ffmpeg:new): HLS segmenter doesn't cut properly with AVC Baseline level 3.0

[FFmpeg]

#6868: HLS segmenter doesn't cut properly with AVC Baseline level 3.0
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             Reporter:  beloko  |                     Type:  defect
               Status:  new     |                 Priority:  normal
            Component:  ffmpeg  |                  Version:  git-master
             Keywords:  HLS     |               Blocked By:
             Blocking:          |  Reproduced by developer:  0
Analyzed by developer:  0       |
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 For a better Apple HLS compatibility with older devices, it's better to
 provide LD and SD quality streams into MPEG2-TS AVC Baseline Level 3.0.
 And it requires less CPU charge to decode with an old mobile processor.

 [[Image(https://developer.apple.com/library/content/technotes/tn2224/Art/tn2224_hw_limitations.jpg)]]
 Source :
 https://developer.apple.com/library/content/technotes/tn2224/_index.html

 So I would like to produce HLS streams compliant with the Baseline 3.0
 profile using FFMPEG.

 In my FFMPEG command line, I use ''-vprofile baseline'' and ''-vlevel
 3.0'' arguments to provide this specification to the libx264. Like this :


 {{{
 ffmpeg.exe -i "D:\Video Samples\Sony_Alpha_7R_II_video-test-4K.mp4"
 -loglevel verbose -threads 0 -c:a libfdk_aac -sn -vcodec libx264 -vprofile
 baseline -vlevel 3.0 -force_key_frames "expr:gte(t,n_forced*4)" -r 25 -f
 hls -hls_time 4 -hls_list_size 99999 -start_number 1 -hls_segment_type
 mpegts "C:\Users\Beloko\Desktop\Sony_Alpha_7R_II_video-test-4K.m3u8"
 }}}


 To be sure the HLS segmenter works properly and create perfect TS files, I
 use the ''-force_key_frame'' parameter and I fix the framerate. Each TS
 file should be exactly 4 second long.

 But unfortunately the first TS, and only the first TS hasn't the good time
 length. Here is the .M3U8 content.


 {{{
 #EXTM3U
 #EXT-X-VERSION:3
 #EXT-X-TARGETDURATION:5
 #EXT-X-MEDIA-SEQUENCE:1
 #EXTINF:4.042667,
 Sony_Alpha_7R_II_video-test-4K1.ts
 #EXTINF:4.000000,
 Sony_Alpha_7R_II_video-test-4K2.ts
 #EXTINF:4.000000,
 Sony_Alpha_7R_II_video-test-4K3.ts
 #EXTINF:4.000000,
 Sony_Alpha_7R_II_video-test-4K4.ts
 #EXTINF:4.000000,
 Sony_Alpha_7R_II_video-test-4K5.ts
 #EXTINF:4.000000,
 Sony_Alpha_7R_II_video-test-4K6.ts
 ...
 }}}


 The #EXT-X-TARGETDURATION: value should be 4 and not 5. And the first
 #EXTINF: value should be 4.000000 and not 4.042667.

 And FFPROBE detect a duration of 00:00:04.05 instead of 00:00:04.00.

 To solve this issue I found two ways :
 . replace ''-c:a libfdk_aac'' by ''-an'' (this means no audio)
 . or replace ''-vprofile baseline'' by ''-vprofile main'' (this means
 enable BFrames)

 But old HLS players don't support BFrames and separated audio tracks (like
 multiple audio language).

 I tested to encode audio with ''-c:a aac'' and ''-c:a'' libmp3lame with no
 more luck. And I also tested with many other video files. It produce the
 same issue.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6868>
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