[FFmpeg-trac] #9918(undetermined:new): Reading/Saving DASH live stream is laggy

[FFmpeg]

#9918: Reading/Saving DASH live stream is laggy
-------------------------------------+-------------------------------------
             Reporter:  mrskman      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 Saving DASH live stream results in laggy video.

 How to reproduce:
 {{{
 ffmpeg -re -i
 'https://livesim.dashif.org/livesim/periods_20/testpic_2s/Manifest.mpd' -y
 test.mp4
 ffmpeg version 5.1.1 Copyright (c) 2000-2022 the FFmpeg developers
   built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
   configuration: --prefix=/opt/ffmpeg/5.1.1/build --cc= --cxx= --objcc=
 --dep-cc= --extra-cflags=' -I/usr/local/cuda-11.7/include' --extra-
 cxxflags= --extra-ldflags='-Wl,-rpath,/opt/ffmpeg/5.1.1/build/lib
 -L/opt/ffmpeg/5.1.1/build/lib -Wl,-rpath,/usr/local/cuda-11.7/lib64
 -L/usr/local/cuda-11.7/lib64' --bindir=/opt/ffmpeg/5.1.1/build/bin
 --enable-shared --disable-static --disable-doc --disable-htmlpages
 --disable-manpages --disable-podpages --disable-txtpages --enable-cuda-
 nvcc --enable-gpl --enable-libaom --enable-libfdk-aac --enable-libmp3lame
 --enable-libnpp --enable-libopenjpeg --enable-libopus --enable-librtmp
 --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libwebp
 --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg
 --enable-nonfree --enable-nvdec --enable-nvenc --enable-openssl --enable-
 rpath --enable-version3
   libavutil      57. 28.100 / 57. 28.100
   libavcodec     59. 37.100 / 59. 37.100
   libavformat    59. 27.100 / 59. 27.100
   libavdevice    59.  7.100 / 59.  7.100
   libavfilter     8. 44.100 /  8. 44.100
   libswscale      6.  7.100 /  6.  7.100
   libswresample   4.  7.100 /  4.  7.100
   libpostproc    56.  6.100 / 56.  6.100
 Input #0, dash, from
 'https://livesim.dashif.org/livesim/periods_20/testpic_2s/Manifest.mpd':
   Metadata:
     Title           : Media Presentation Description from DASH-IF live
 simulator
   Duration: N/A, start: 1662761184.066667, bitrate: N/A
   Program 0
   Stream #0:0: Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360,
 30 fps, 30 tbr, 90k tbn (default)
     Metadata:
       variant_bitrate : 300000
       id              : V300
   Stream #0:1(en): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo,
 fltp (default)
     Metadata:
       variant_bitrate : 48000
       id              : A48
 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
 [libx264 @ 0x55b125a2c800] using cpu capabilities: MMX2 SSE2Fast SSSE3
 SSE4.2 AVX FMA3 BMI2 AVX2
 [libx264 @ 0x55b125a2c800] profile Progressive High, level 3.0, 4:2:0,
 8-bit
 [libx264 @ 0x55b125a2c800] 264 - core 157 - H.264/MPEG-4 AVC codec -
 Copyleft 2003-2019 - http://www.videolan.org/x264.html - options: cabac=1
 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1
 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1
 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=11
 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0
 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25
 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0
 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
 Output #0, mp4, to 'test.mp4':
   Metadata:
     Title           : Media Presentation Description from DASH-IF live
 simulator
     encoder         : Lavf59.27.100
   Stream #0:0: Video: h264 (avc1 / 0x31637661), yuv420p(progressive),
 640x360, q=2-31, 30 fps, 15360 tbn (default)
     Metadata:
       variant_bitrate : 300000
       id              : V300
       encoder         : Lavc59.37.100 libx264
     Side data:
       cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
   Stream #0:1(en): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo,
 fltp, 128 kb/s (default)
     Metadata:
       variant_bitrate : 48000
       id              : A48
       encoder         : Lavc59.37.100 aac
 frame= 1124 fps= 28 q=29.0 size=     256kB time=00:00:35.94 bitrate=
 58.4kbits/s dup=540 drop=0 speed=0.909x
 }}}

 Try to play the resulting test.mp4 file. It is not as smooth as the
 source. Video periodically hangs.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9918>
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