ffplay doesn't play dash format with presentationTimeOffset.

[satbaby]

Summary of the bug:
here are two examples:
​https://livesim.dashif.org/livesim/periods_60/continuous_1/testpic_2s/Manifest.mpd
​https://akamai-axtest.akamaized.net/routes/lapd-v1-acceptance/www_c4/Manifest.mpd

How to reproduce:

ffplay https://livesim.dashif.org/livesim/periods_60/continuous_1/testpic_2s/Manifest.mpd
ffplay version N-91691-g962c9313af Copyright (c) 2003-2018 the FFmpeg developers
  built with gcc 8.2.0 (Gentoo 8.2.0-r2 p1.2)
  configuration: --prefix=/mnt/BIG/ffmpeg/root/ --disable-doc --disable-stripping --enable-debug=1 --enable-libxml2 --enable-demuxer=dash --enable-openssl
  libavutil      56. 19.100 / 56. 19.100
  libavcodec     58. 25.100 / 58. 25.100
  libavformat    58. 17.103 / 58. 17.103
  libavdevice    58.  4.101 / 58.  4.101
  libavfilter     7. 26.100 /  7. 26.100
  libswscale      5.  2.100 /  5.  2.100
  libswresample   3.  2.100 /  3.  2.100
[dash @ 0x7f2328000b80] Could not read complete fragment.0B f=0/0   
[https @ 0x7f232800aa00] HTTP error 404 Not Found sq=    0B f=0/0   
[dash @ 0x7f2328000b80] Failed to open fragment of playlist 0                                                                                                                     
[https @ 0x7f2328017e40] HTTP error 404 Not Found sq=    0B f=0/0   
[dash @ 0x7f2328000b80] Failed to open fragment of playlist 0                                                                                                                     
[https @ 0x7f232804a440] HTTP error 404 Not Found sq=    0B f=0/0   
[dash @ 0x7f2328000b80] Failed to open fragment of playlist 0                                                                                                                     
[https @ 0x7f2328041240] HTTP error 404 Not Found sq=    0B f=0/0   
[dash @ 0x7f2328000b80] Failed to open fragment of playlist 0                                                                                                                     
[https @ 0x7f232804e040] HTTP error 404 Not Found sq=    0B f=0/0   
[dash @ 0x7f2328000b80] Failed to open fragment of playlist 0                                                                                                                     
[https @ 0x7f2328041340] HTTP error 404 Not Found sq=    0B f=0/0   
[dash @ 0x7f2328000b80] Failed to open fragment of playlist 0
[https @ 0x7f2328018580] HTTP error 404 Not Found sq=    0B f=0/0   
[dash @ 0x7f2328000b80] Failed to open fragment of playlist 0
[https @ 0x7f2328054a40] HTTP error 404 Not Found sq=    0B f=0/0   
[dash @ 0x7f2328000b80] Failed to open fragment of playlist 0

I have patch, but no idea if is correct:

cat /tmp/try_to_fix_calc_cur_seg_no_with_presentation_timeoffset.diff 
diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
index c6dddeb98f..fe6d95102b 100644
--- a/libavformat/dashdec.c
+++ b/libavformat/dashdec.c
@@ -1294,7 +1294,7 @@ static int64_t calc_cur_seg_no(AVFormatContext *s, struct representation *pls)
                 num += pls->first_seq_no;
         } else if (pls->fragment_duration){
             if (pls->presentation_timeoffset) {
-                num = pls->presentation_timeoffset * pls->fragment_timescale / pls->fragment_duration;
+                num = pls->first_seq_no + (((get_current_time_in_sec() * pls->fragment_timescale)-pls->presentation_timeoffset) / pls->fragment_duration) - 120;
             } else if (c->publish_time > 0 && !c->availability_start_time) {
                 num = pls->first_seq_no + (((c->publish_time - c->availability_start_time) - c->suggested_presentation_delay) * pls->fragment_timescale) / pls->fragment_duration;
             } else {

[Carl Eugen Hoyos]

Please send your patch - made with git format-patch - to the FFmpeg development mailing list, patches are ignored on this bug tracker.

[satbaby]

@ Steven Liu
Now with you patch ​https://patchwork.ffmpeg.org/patch/10218/ work ok.

[Steven Liu]

fixed by commit id: ad9b4ecc26bef7babb31b58f19c869f6464c2db9

[Carl Eugen Hoyos]

Replying to satbaby:

​https://livesim.dashif.org/livesim/periods_60/continuous_1/testpic_2s/Manifest.mpd

There is still an issue with this stream afaict.

[Steven Liu]

Replying to cehoyos:

Replying to satbaby:

​https://livesim.dashif.org/livesim/periods_60/continuous_1/testpic_2s/Manifest.mpd

There is still an issue with this stream afaict.

fixed by : 7bb90a9449bc845ffbde0eea0dfcaf2b3eed4256