On Fri, 2 Aug 2024, 17:49 Anton Kapela, <tkap...@gmail.com> wrote: > To my ffmpeg brethren: > > I'm trying to share some fun content with the world, specifically an > off-air feed from France 2 (which has the Olympics, bcast in UHD, 50 fps, > main 10, full-on BT2020 with PQ HDR, at ~18 mbits composite TS rate), and > am absolutely confounded. Hoping that someone here knows how fMP4 a/v > interleaving and sync is supposed to work. > > Find the live fMP4 HLS here: > https://endpnt.com/hls/france2uhd/france2uhd.m3u8 > > When playing this HLS on iOS or macOS Safari, we get: frame > re-ordering (ie. "jumps") at what appear to be approximately fMP4 chunk > boundaries, audio is several seconds behind, despite audio and video > quickly decoding and playing upon starting the stream. Playing the same in > VLC, we start decoding frames immediately after downloading the first few > chunks, but no audio will play until several seconds have elapsed - so, no > a/v sync here. However, no inter-fragment frame reordering/jumps between > fragments. > > Using MPV and ffplay, *things work* - a/v is sync'd, and doesn't drift when > playing the stream for arbitrarily long durations. > > If I switch from fMP4 chunks to good ol' TS chunks, everything but Safari > plays just fine - a/v sync intact, etc. Of course, we know AAPL will never > support HEVC in .TS chunks, so I'd like to use fMP4. > > In examining the mp4 init and the other mp4 segments produced by ffmpeg > (tried 4.3.7-old, 6.0.1, 7.0, 7.1, and git-current via JVS's "static > ffmpeg" builds on several different linux distributions), everything looks > kosher. We get the right ATOMs where expected (AFAICT), we are told about > frame durations in the codec, and the decoder can plainly see how many > samples are in each EAC3 packet as muxed in the mp4 fragments. > > Things I've tried in adjusting the input/output of ffmpeg, which have not > resolved/changed anything regarding this "a/v desync on some players but > not all" issue: > > -copyts, -reset_timestamps 1, -use_wallclock_as_timestamps, -async, > -fps_mode drop, -r 50, -re, etc. > -transcoding audio to aac, regular ac3, and mp3 (also at 44.1k rate vs. the > bcast source of 48khz) > -different segment lengths > -ss n (which doesn't do anything, as the stream is not seekable) > -fflags +nobuffer and various exhaustive combinations of -experimental low > latency options > -max_muxing_queue_size 9999 -max_interleave_delta 0 and other muxer-tweaks > -manually rewriting audio timestamps with setpts into the future (seems to > not carry over into fMP4, does seem to work in TS, but we don't want that) > > Here's what's being ran, and what one could use to replicate this problem > on their system (assuming you have access and can sustain 18 mbits from my > .ts relay server, running icecast-kh): > > ffmpeg -icy 0 -i http://endpnt.com:8000/france-2-uhd.ts -vcodec copy > -acodec copy -tag:v hvc1 -b:v 18M -map 0:i:3021 -map 0:i:3032 > -hls_segment_type fmp4 -hls_init_time 4 -hls_list_size 10 -hls_time 4 > -hls_flags iframes_only+independent_segments+delete_segments > france2uhd.m3u8 > > No useful "errors" (other than normal AC3 implied vs. explicit sample > lengths) or cli output from ffmpeg exist here, as there's nothing to > report. I've included the last bit of input detection, fmp4 stuff firing > up, and then a little runtime output after this note in case anyone is > curious. > > Clues welcome & appreciated. > > Best, > > -Tk > > [hevc @ 0x55f6ac243700] Error parsing NAL unit #2. > [hevc @ 0x55f6ac243700] PPS id out of range: 0 > Last message repeated 1 times > [hevc @ 0x55f6ac243700] Error parsing NAL unit #2. > [hevc @ 0x55f6ac243700] PPS id out of range: 0 > Last message repeated 1 times > [hevc @ 0x55f6ac243700] Error parsing NAL unit #2. > [hevc @ 0x55f6ac243700] PPS id out of range: 0 > Last message repeated 1 times > [hevc @ 0x55f6ac243700] Error parsing NAL unit #2. > [hevc @ 0x55f6ac243700] PPS id out of range: 0 > Last message repeated 1 times > [hevc @ 0x55f6ac243700] Error parsing NAL unit #2. > Input #0, mpegts, from 'http://endpnt.com:8000/france-2-uhd.ts': > Duration: N/A, start: 41795.243156, bitrate: N/A > Program 2305 > Stream #0:0[0xbcd]: Video: hevc (Main 10) ([36][0][0][0] / 0x0024), > yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x2160 [SAR 1:1 DAR 16:9], > 50 fps, 50 tbr, 90k tbn, 50 tbc > Stream #0:1[0xbce]: Data: bin_data (AC-4 / 0x342D4341) > Stream #0:2[0xbd8](fre): Audio: eac3 ([6][0][0][0] / 0x0006), 48000 Hz, > stereo, fltp, 128 kb/s > Stream #0:3[0xbd9](qaa): Audio: eac3 ([6][0][0][0] / 0x0006), 48000 Hz, > stereo, fltp, 128 kb/s > Stream #0:4[0xbda](fre): Audio: eac3 ([6][0][0][0] / 0x0006), 48000 Hz, > stereo, fltp, 128 kb/s (visual impaired) (descriptions) > Stream #0:5[0xbdb](fre): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006) > (hearing impaired) > Stream #0:6[0xbdc](fre): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006) > [hls @ 0x55f6ac2cae00] Opening 'init.mp4' for writing > [mp4 @ 0x55f6ac227a80] track 1: codec frame size is not set > Output #0, hls, to 'france2uhd.m3u8': > Metadata: > encoder : Lavf58.45.100 > Stream #0:0: Video: hevc (Main 10) (hvc1 / 0x31637668), yuv420p10le(tv, > bt2020nc/bt2020/smpte2084), 3840x2160 [SAR 1:1 DAR 16:9], q=2-31, 18000 > kb/s, 50 fps, 50 tbr, 12800 tbn, 50 tbc > Stream #0:1(fre): Audio: eac3 ([6][0][0][0] / 0x0006), 48000 Hz, > stereo, fltp, 128 kb/s > Stream mapping: > Stream #0:0 -> #0:0 (copy) > Stream #0:2 -> #0:1 (copy) > Press [q] to stop, [?] for help > [hls @ 0x55f6ac2cae00] Opening 'france2uhd0.m4s' for writing=N/A > speed=2.11x > [hls @ 0x55f6ac2cae00] Opening 'france2uhd.m3u8.tmp' for writing > [hls @ 0x55f6ac2cae00] Opening 'france2uhd1.m4s' for writing=N/A > speed=1.55x > [hls @ 0x55f6ac2cae00] Opening 'france2uhd.m3u8.tmp' for writing > [hls @ 0x55f6ac2cae00] Opening 'france2uhd2.m4s' for writing=N/A > speed=1.34x > [hls @ 0x55f6ac2cae00] Opening 'france2uhd.m3u8.tmp' for writing > frame= 737 fps= 55 q=-1.0 size=N/A time=00:00:16.70 bitrate=N/A > speed=1.25x >
Use this: ffmpeg -icy 0 -i http://endpnt.com:8000/france-2-uhd.ts -vcodec copy -acodec copy -tag:v hvc1 -b:v 18M -map 0:i:3021 -map 0:i:3032 -flags +global_header -f hls -hls_segment_type fmp4 -hls_init_time 4 -hls_list_size 10 -hls_time 4 -hls_flags +split_by_time+delete_segments france2uhd.m3u8 Report back with findings. > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
