February 2020 - ffmpeg-user - lists.ffmpeg.org

From .m4s to .ts
by Jesús Aguilar Armijo 20 Feb '20

20 Feb '20

Dear ffmpeg community. I want to perform a repackaging from .m4s (DASH segments) to .ts (HLS segments). Is that possible to do with FFmpeg? How can I proceed? Thank you very much for your help. Kind regards.

3 2

http_persistent not honored when encryption is enabled
by Valentin Schweitzer 20 Feb '20

20 Feb '20

Hi, Enabling http_persistent and encryption in the hls muxer leads to HTTP connections that multiple Web servers cannot deal with properly. In particular, ffmpeg sends HTTP PUT requests with a "Connection: keep-alive" header for each segment file, but it closes the connection right afterwards and opens a new one for the next segment. I can observe this behavior with Wireshark and multiple different Web servers, e.g., Apache, Kestrel and tornado. Using the most recent zeranoe build of ffmpeg for 64-bit Windows, .\ffmpeg -y -hide_banner -f lavfi -i color=c=black:s=1920x1080:r=25 -vcodec libx264 -f hls -hls_segment_type mpegts -hls_time 0.04 -hls_list_size 100 -hls_flags second_level_segment_index+split_by_time+program_date_time -hls_init_time 0.04 -http_persistent 1 -strftime 1 -hls_segment_filename http://127.0.0.1:45000/%%18d.ts -hls_enc 1 -hls_enc_key fedcba9876543210 -hls_enc_iv fedcba9876543210 -method PUT http://127.0.0.1:45000/index.m3u8 shows the described behavior of connections being closed despite http_persistent being enabled and keep-alive being sent. With loglevel debug, it is visible that a connection is started for each segment, but the closing of the connection is only implicitly visible due to the statistics being printed (the closing can be seen more clearly with the FIN ACK in Wireshark): [..] [hls @ 000001cf588da0c0] Opening 'crypto:http://127.0.0.1:45000/streams/-/data/1080p/000000000000000011.ts' for writing [crypto @ 000001cf588e6f80] No default whitelist set [http @ 000001cf588e6180] Setting default whitelist 'http,https,tls,rtp,tcp,udp,crypto,httpproxy' [tcp @ 000001cf588e7540] Original list of addresses: [tcp @ 000001cf588e7540] Address 127.0.0.1 port 45000 [tcp @ 000001cf588e7540] Interleaved list of addresses: [tcp @ 000001cf588e7540] Address 127.0.0.1 port 45000 [tcp @ 000001cf588e7540] Starting connection attempt to 127.0.0.1 port 45000 [tcp @ 000001cf588e7540] Successfully connected to 127.0.0.1 port 45000 [http @ 000001cf588e6180] request: PUT /streams/-/data/1080p/000000000000000011.ts HTTP/1.1 Transfer-Encoding: chunked User-Agent: Lavf/58.35.100 Accept: */* Connection: keep-alive Host: 127.0.0.1:45000 Icy-MetaData: 1 [AVIOContext @ 000001cf59a466c0] Statistics: 0 seeks, 1 writeouts [hls @ 000001cf588da0c0] Opening 'http://127.0.0.1:45000/streams/-/data/1080p/index.m3u8' for writing [..] When encryption is disabled, .\ffmpeg -y -hide_banner -f lavfi -i color=c=black:s=1920x1080:r=25 -vcodec libx264 -f hls -hls_segment_type mpegts -hls_time 0.04 -hls_list_size 100 -hls_flags second_level_segment_index+split_by_time+program_date_time -hls_init_time 0.04 -http_persistent 1 -strftime 1 -hls_segment_filename http://127.0.0.1:45000/%%18d.ts -method PUT http://127.0.0.1:45000/index.m3u8 the connection is left open as it should be. This is also visible with loglevel debug (note the missing statistics for the closed connection): [..] [http @ 000001f9bd0e7880] Opening 'http://127.0.0.1:45000/streams/-/data/1080p/000000000000000011.ts' for writing [http @ 000001f9ba626d40] request: PUT /streams/-/data/1080p/000000000000000011.ts HTTP/1.1 Transfer-Encoding: chunked User-Agent: Lavf/58.35.100 Accept: */* Connection: keep-alive Host: 127.0.0.1:45000 Icy-MetaData: 1 [http @ 000001f9bd0e7880] Opening 'http://127.0.0.1:45000/streams/-/data/1080p/index.m3u8' for writing [..] *QUESTION*: How can I get ffmpeg to keep the connection open also when encryption is enabled? Greetings, Valentin PS.: Looking at the source code, the connection closing logic in hlsenc_io_close (https://github.com/FFmpeg/FFmpeg/blob/bb01baae269cd2d7a0e61dc9bf327168edd43…) seems to differ from the opening logic in hlsenc_io_open (https://github.com/FFmpeg/FFmpeg/blob/bb01baae269cd2d7a0e61dc9bf327168edd43…) The difference seems to be related only to encryption. However, if I remove "|| hls->key_info_file || hls->encrypt" in hlsenc_io_close to make the it symmetric to hlsenc_io_open, the connections are still closed, but with slightly different packets in the lower TCP/IP layers. The issue remains.

3 4

remap filter, unmapped pixels
by Michael Koch 20 Feb '20

20 Feb '20

I'd like to understand how the new "fill" option in the remap filter works. What is an "unmapped pixel"? How is it possible that pixels are unmapped, if the xmap and ymap files have the same size as the output image? Is a pixel "unmapped" if it has invalid coordinates (negative or too big) in the xmap or ymap files? Michael

2 9

FFmpeg do not activate stream capture on MS Surface Pro 7 Rear camera
by IT 20 Feb '20

20 Feb '20

Hi, MS Surface Pro 7 rear camera does not activate when trying to capture stream. This is the command I am using : ffmpeg.exe -f dshow -i video="Surface Camera Rear" -f mpeg1video http://127.0.0.1:8082/test/640/360 ffmpeg version git-2020-02-16-8578433 Copyright (c) 2000-2020 the FFmpeg developers built with gcc 9.2.1 (GCC) 20200122 configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf libavutil 56. 41.100 / 56. 41.100 libavcodec 58. 70.100 / 58. 70.100 libavformat 58. 38.101 / 58. 38.101 libavdevice 58. 9.103 / 58. 9.103 libavfilter 7. 76.100 / 7. 76.100 libswscale 5. 6.100 / 5. 6.100 libswresample 3. 6.100 / 3. 6.100 libpostproc 55. 6.100 / 55. 6.100 Same command with Front camera is activating the stream : ffmpeg.exe -f dshow -framerate 29.97 -i video="Surface Camera Front" -f mpeg1video http://127.0.0.1:8082/test/640/360 ffmpeg version git-2020-02-16-8578433 Copyright (c) 2000-2020 the FFmpeg developers built with gcc 9.2.1 (GCC) 20200122 configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf libavutil 56. 41.100 / 56. 41.100 libavcodec 58. 70.100 / 58. 70.100 libavformat 58. 38.101 / 58. 38.101 libavdevice 58. 9.103 / 58. 9.103 libavfilter 7. 76.100 / 7. 76.100 libswscale 5. 6.100 / 5. 6.100 libswresample 3. 6.100 / 3. 6.100 libpostproc 55. 6.100 / 55. 6.100 Input #0, dshow, from 'video=Surface Camera Front': Duration: N/A, start: 277359.143000, bitrate: N/A Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x360, 30 fps, 30 tbr, 10000k tbn, 10000k tbc Stream mapping: Stream #0:0 -> #0:0real-time buffer [Surface Camera Front] [video input] too full or near too full (90% of size: 3041280 [rtbufsize parameter])! frame dropped! (rawvideo (native) -> mpeg1video (native)) Press [q] to stop, [?] for help [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (90% of size: 3041280 [rtbufsize parameter])! frame dropped! Last message repeated 1 times Output #0, mpeg1video, to 'http://127.0.0.1:8082/test/640/360': [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (106% of size: 3041280 [rtbufsize parameter])! frame dropped! Metadata: encoder : Lavf58.38.101 Stream #0:0: Video: mpeg1video, yuv420p, 640x360, q=2-31, 200 kb/s, 30 fps, real-time buffer [Surface Camera Front] [video input] too full or near too full (106% of size: 3041280 [rtbufsize parameter])! frame dropped! 30 tbn, 30 tbc Metadata: encoder : real-time buffer [Surface Camera Front] [video input] too full or near too full (106% of size: 3041280 [rtbufsize parameter])! frame dropped! Lavc58.70.100 mpeg1video [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (106% of size: 3041280 [rtbufsize parameter])! frame dropped! Side data: cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: N/Areal-time buffer [Surface Camera Front] [video input] too full or near too full (106% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (90% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! Last message repeated 1 times [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (90% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (90% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (90% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (90% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (90% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (106% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (75% of size: 3041280 [rtbufsize parameter])! frame dropped! Last message repeated 1 times [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (106% of size: 3041280 [rtbufsize parameter])! frame dropped! frame= 2796 fps= 29 q=16.4 Lsize= 2676kB time=00:01:33.16 bitrate= 235.3kbits/s dup=890 drop=86 speed=0.979x video:2676kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000% [dshow @ 000001fecd259a00] real-time buffer [Surface Camera Front] [video input] too full or near too full (106% of size: 3041280 [rtbufsize parameter])! frame dropped! Exiting normally, received signal 2. Any help would be appreciated. Regards, Benoit

2 1

Using FFMpeg to produce LL-HLS
by Simon Brown 20 Feb '20

20 Feb '20

I'm trying to reduce the latency of streaming video to a web page. I have tried a few options: 1) WebRTC - great, but doesn't support interlaced video 2) fMP4 - couldn't get a working solution 3) HLS - great, plays interlaced video as well, but latency is appalling 4) LL-HLS - can't find anything that produces it. Does FFMpeg support generating LL-HLS? Regards, Simon

5 12

hls and input http stream changes problem
by Michal Hajek 19 Feb '20

19 Feb '20

Hi, I need to generate one endless hls stream from endless input http stream. The input http stream is made from a few input files in a loop (using VLC 3.0.8). The ffmpeg command: .\ffmpeg -i http://10.200.100.79:8024 -c:v libx264 -crf 25 -preset veryfast ^ -tune fastdecode -hls_allow_cache 0 ^ -c:a aac -filter:a "volume=0.10" -f hls -hls_segment_type fmp4 ^ -hls_flags delete_segments+discont_start+omit_endlist ^ -g 25 -sc_threshold 0 stream.m3u8 And the output is: ..... [hls @ 066e6d40] Opening 'stream0.m4s' for writing57 bitrate=N/A speed=5.16x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream1.m4s' for writing [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream2.m4s' for writing63 bitrate=N/A speed=4.42x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [mp4 @ 084d6180] Application provided duration: -1 / timestamp: 288379 is out of range for mov/mp4 format [hls @ 066e6d40] Opening 'stream3.m4s' for writing46 bitrate=N/A speed= 2.5x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream4.m4s' for writing34 bitrate=N/A speed=1.96x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream5.m4s' for writing73 bitrate=N/A speed=1.67x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream6.m4s' for writing41 bitrate=N/A speed=1.55x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream7.m4s' for writing76 bitrate=N/A speed=1.42x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream8.m4s' for writing68 bitrate=N/A speed=1.37x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream9.m4s' for writing37 bitrate=N/A speed=1.33x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream10.m4s' for writing9 bitrate=N/A speed=1.29x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream11.m4s' for writing4 bitrate=N/A speed=1.26x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream12.m4s' for writing7 bitrate=N/A speed=1.24x [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing <---- so far so good, but here VLC starts streaming of next file [mpegts @ 003d0200] New audio stream 0:2 at pos:12504256 and DTS:62584.9s23x <---- ffmpeg detects change in input stream [mpegts @ 003d0200] New video stream 0:3 at pos:12505760 and DTS:62585s1.21x <---- but stops creating hls files [mpegts @ 003d0200] New audio stream 0:4 at pos:14497432 and DTS:62595.7s835x <--- here VLC starts streamig next file [mpegts @ 003d0200] New video stream 0:5 at pos:14508336 and DTS:62595.7s <--- still no new hls files [mpegts @ 003d0200] New audio stream 0:6 at pos:20390856 and DTS:62612.9s578x <--- here VLC starts streamig next file [mpegts @ 003d0200] New video stream 0:7 at pos:20401760 and DTS:62613.3s554x <---- I pressed CTRL-C in ffmpeg [hls @ 066e6d40] Opening 'stream13.m4s' for writing3 bitrate=N/A speed=0.508x <---- ffmpeg starts correct shutdown [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing [hls @ 066e6d40] Opening 'stream14.m4s' for writing [hls @ 066e6d40] Opening 'stream.m3u8.tmp' for writing frame= 704 fps= 13 q=-1.0 Lsize=N/A time=00:00:28.17 bitrate=N/A speed=0.504x video:3572kB audio:454kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown [libx264 @ 003db640] frame I:29 Avg QP:22.27 size: 33274 [libx264 @ 003db640] frame P:459 Avg QP:25.30 size: 5259 [libx264 @ 003db640] frame B:216 Avg QP:28.36 size: 1286 [libx264 @ 003db640] consecutive B-frames: 51.8% 15.6% 18.3% 14.2% [libx264 @ 003db640] mb I I16..4: 11.6% 45.7% 42.7% [libx264 @ 003db640] mb P I16..4: 2.9% 9.9% 0.9% P16..4: 29.2% 8.5% 2.3% 0.0% 0.0% skip:46.3% [libx264 @ 003db640] mb B I16..4: 0.5% 1.8% 0.0% B16..8: 8.8% 2.5% 0.3% direct: 3.6% skip:82.5% L0:43.0% L1:36.5% BI:20.5% [libx264 @ 003db640] 8x8 transform intra:64.7% inter:54.9% [libx264 @ 003db640] coded y,uvDC,uvAC intra: 57.7% 53.5% 13.4% inter: 8.6% 6.9% 0.3% [libx264 @ 003db640] i16 v,h,dc,p: 38% 37% 15% 10% [libx264 @ 003db640] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 24% 35% 2% 3% 3% 2% 3% 4% [libx264 @ 003db640] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 21% 11% 6% 7% 8% 7% 7% 7% [libx264 @ 003db640] i8c dc,h,v,p: 43% 26% 24% 7% [libx264 @ 003db640] kb/s:1038.85 [aac @ 066c0a40] Qavg: 9562.674 Exiting normally, received signal 2. What parameters make ffmpeg to accept all input streams? Thanks, Michal

3 5

Ffmeg multi-threading introduction
by Mohammed Bey Ahmed Khernache 19 Feb '20

19 Feb '20

Hello, I am novice to programming upon ffmpeg. I would like to know how ffmpeg manages to decode multiple regions of a frame (slices, tiles, NALs, etc) in parallel. Could you point me to the files/functions that do this job? Best regards

3 2

Question
by CheeZe AMV's 18 Feb '20

18 Feb '20

Hi. I have a question about ffmpeg. I just started using it this week, so I'm a complete newbie to all of this. Any help is appreciated. I'm trying to download from a subscription service website that I am subscribed to and the downloading works, but more often than not I get the message "skipping 1 segments ahead expired from playlists" while it's downloading in the command line. This ranges from 1 to other numbers as well. Here below is the template I'm using: ffmpeg -i "m3u8 master playlist url" -c copy -bsf:a aac_adtstoasc "example.mp4" Would you be able to help me with why there are skipped segments and how I can avoid them? Because after it's downloaded there are frames in the video that are frozen. The website I am referring to is: https://ch.nicovideo.jp/nicopro if that's of any assistance. Also, if you don't mind would you be able to template the solution in a similar format that I have, that would be of great help. Kind regards Khaled Hoque

4 8

Low-quality transcode
by Wouter Verhelst 17 Feb '20

17 Feb '20

Hi list, I'm a member of the FOSDEM video team. I wrote a tool to automatically review and transcode FOSDEM video recordings, written in Perl, which simply calls ffmpeg and ffprobe to do all the hard work[1]. It works well, but there's something that's a bit weird. For one particular talk, the quality of the transcode from MP4 to WebM is very low. I use VBR encoding, but in most cases I end up with a transcoded file that is about 60-70% of the size of the original file. In one particular case, however, the file ends up being less than 50% of the original file, and the quality is very low; the transcoded file ends up having very visible encoder artifacts: https://video.fosdem.org/2020/AW1.125/ada_rad.webm Note the camera PIP at the bottom right corner, where smears etc are clearly visible. The command line that was originally used is this one: 'ffmpeg' '-loglevel' 'warning' '-y' '-f' 'concat' '-safe' '0' '-i' '/tmp/transSnsDON/concat.txt' '-c:v' 'libvpx-vp9' '-b:v' '1024k' '-minrate' '512k' '-maxrate' '1484.8k' '-r:v' '25/1' '-crf' '32' '-speed' '4' '-pass' '1' '-passlogfile' '/srv/sreview/output/2020/AW1.125/ada_rad.webm-multipass' '-c:a' 'libopus' '-b:a' '128k' '-ar' '48000' '-t' '1331.934' '-pix_fmt' 'yuv420p' '-metadata' 'title=On Rapid Application Development in Ada' '-metadata' 'event=FOSDEM 2020' '-metadata' 'speakers=Tomasz Maluszycki' '-metadata' 'date=2020-02-01' '/srv/sreview/output/2020/AW1.125/ada_rad.webm' 'ffmpeg' '-loglevel' 'warning' '-y' '-f' 'concat' '-safe' '0' '-i' '/tmp/transSnsDON/concat.txt' '-c:v' 'libvpx-vp9' '-b:v' '1024k' '-minrate' '512k' '-maxrate' '1484.8k' '-r:v' '25/1' '-crf' '32' '-speed' '2' '-pass' '2' '-passlogfile' '/srv/sreview/output/2020/AW1.125/ada_rad.webm-multipass' '-c:a' 'libopus' '-b:a' '128k' '-ar' '48000' '-t' '1331.934' '-pix_fmt' 'yuv420p' '-metadata' 'title=On Rapid Application Development in Ada' '-metadata' 'event=FOSDEM 2020' '-metadata' 'speakers=Tomasz Maluszycki' '-metadata' 'date=2020-02-01' '/srv/sreview/output/2020/AW1.125/ada_rad.webm' which are the same settings as used for all other videos (and those seem to be fine). I first thought I'd just tweak things a bit, and tried changing the bitrate values in the above command line to '-b:v' '1800k' '-minrate' '900k' '-maxrate' '2610k', with everything else remaining the same. That didn't result in any visible difference. Next, I bumped -minrate to '1500k', and left -b:v and -maxrate to the 1800 and 2610k settings. That also didn't result in any visible difference. I'm beginning to think that perhaps I've found a bug in ffmpeg. Any thoughts? The ffmpeg version used is the one packaged in Debian buster: ffmpeg version 4.1.4-1~deb10u1 Copyright (c) 2000-2019 the FFmpeg developers built with gcc 8 (Debian 8.3.0-6) configuration: --prefix=/usr --extra-version='1~deb10u1' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared libavutil 56. 22.100 / 56. 22.100 libavcodec 58. 35.100 / 58. 35.100 libavformat 58. 20.100 / 58. 20.100 libavdevice 58. 5.100 / 58. 5.100 libavfilter 7. 40.101 / 7. 40.101 libavresample 4. 0. 0 / 4. 0. 0 libswscale 5. 3.100 / 5. 3.100 libswresample 3. 3.100 / 3. 3.100 libpostproc 55. 3.100 / 55. 3.100 The input video files are removed at the end of the transcode process, so I cannot produce those; however, the .mp4 files are created with '-c:v copy -c:a copy', so I believe that should be enough for you to reproduce the issue (if not, let me know and I can recreate them). Any insights as to why this is happening would be appreciated. Thanks, [1] https://github.com/yoe/sreview, in case you care. -- <Lo-lan-do> Home is where you have to wash the dishes. -- #debian-devel, Freenode, 2004-09-22

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WebVTT demuxer ignores processing every 1st line of each follow-up HLS webvtt-segment
by Reino Wijnsma 16 Feb '20

16 Feb '20

Hello ffmpeg-user, While reading this <https://github.com/ytdl-org/youtube-dl/issues/18796#issuecomment-583782299> Github-issue-comment and testing the mentioned HLS-webvtt-url I first of all noticed that, unlike the user claims, ffmpeg does demux all the webvtt-segments. Why this is not happening for this user is most likely because of the old ffmpeg-binary he/she uses. Secondly, what does happen is that ffmpeg doesn't remove the 2nd line of each webvtt-segment (except for the 1st segment). The first webvtt-segment, 'https://ga.video.cdn.pbs.org/videos/frontline/8f769cee-b6d6-437d-80b5-74252…': WEBVTT X-TIMESTAMP-MAP=MPEGTS:187507, LOCAL:00:00:00.000 00:13.400 --> 00:17.400 position:10%,start line:85% size:80% ♪ ♪ 00:17.400 --> 00:20.080 position:10%,start line:85% size:80% WAAD (speaking Arabic): [...] 03:11.320 --> 03:13.400 position:10%,start line:85% size:80% (explosion roars) With [ffmpeg -i https://ga.video.cdn.pbs.org/videos/frontline/8f769cee-b6d6-437d-80b5-74252… 00003717fes-captions0.vtt] ffmpeg converts this to... WEBVTT 00:13.400 --> 00:17.400 ♪ ♪ 00:17.400 --> 00:20.080 WAAD (speaking Arabic): [...] 03:11.320 --> 03:13.400 (explosion roars) ...which is expected. Converting the entire stream with [ffmpeg -i https://ga.video.cdn.pbs.org/videos/frontline/8f769cee-b6d6-437d-80b5-74252… 00003717fes-captions.vtt] ffmpeg puts out... WEBVTT 00:13.400 --> 00:17.400 ♪ ♪ 00:17.400 --> 00:20.080 WAAD (speaking Arabic): [...] 03:11.320 --> 03:13.400 (explosion roars) WEBVTT X-TIMESTAMP-MAP=MPEGTS:187507, LOCAL:00:00:00.000 03:11.320 --> 03:13.400 (explosion roars) [...] 05:56.440 --> 05:59.320 WAAD: WEBVTT X-TIMESTAMP-MAP=MPEGTS:187507, LOCAL:00:00:00.000 06:14.720 --> 06:16.800 (numerous explosions booming) [...] 09:09.400 --> 09:12.960 MAN: WEBVTT X-TIMESTAMP-MAP=MPEGTS:187507, LOCAL:00:00:00.000 09:23.400 --> 09:25.440 SOLDIER: [...] So the very first "WEBVTT\nX-TIMESTAMP-MAP=MPEGTS:187507, LOCAL:00:00:00.000" does become "WEBVTT" and all the following instances (at the beginning of each webvtt-segment) should've been removed, but are simply ignored/copied. Also allowing duplicate entries ("03:11.320 --> 03:13.400\n(explosion roars)") is weird to say the least. FFmpeg used: ffmpeg version N-96249-g81172b5-Reino Copyright (c) 2000-2020 the FFmpeg developers built with gcc 9.2.0 (GCC) configuration: --arch=x86 --target-os=mingw32 --cross-prefix=/cygdrive/m/ffmpeg-windows-build-helpers-master/ffmpeg_local_builds/sandbox/cross_compilers/mingw-w64-i686/bin/i686-w64-mingw32- --pkg-config=pkg-config --pkg-config-flags=--static --extra-version=Reino --enable-gray --enable-version3 --disable-debug --disable-doc --disable-htmlpages --disable-manpages --disable-podpages --disable-txtpages --disable-w32threads --enable-avisynth --enable-frei0r --enable-filter=frei0r --enable-gmp --enable-gpl --enable-libaom --enable-libass --enable-libfdk-aac --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libmp3lame --enable-libopenmpt --enable-libopus --enable-libsoxr --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-mbedtls --extra-cflags='-march=pentium3' --extra-cflags='-mtune=athlon-xp' --extra-cflags=-O2 --extra-cflags='-mfpmath=sse' --extra-cflags=-msse --enable-static --disable-shared --prefix=/cygdrive/m/ffmpeg-windows-build-helpers-master/ffmpeg_local_builds/sandbox/cross_compilers/mingw-w64-i686/i686-w64-mingw32 libavutil 56. 38.100 / 56. 38.100 libavcodec 58. 65.102 / 58. 65.102 libavformat 58. 35.101 / 58. 35.101 libavdevice 58. 9.102 / 58. 9.102 libavfilter 7. 70.101 / 7. 70.101 libswscale 5. 6.100 / 5. 6.100 libswresample 3. 6.100 / 3. 6.100 libpostproc 55. 6.100 / 55. 6.100 -- Reino

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