[FFmpeg-user] Issue with starting ffmpeg

Thu Feb 11 17:46:38 EET 2021

I'm trying to use ffmpeg to stram webrtc. I'm using blackmagic decklink sdi. When I run ffmpeg using the following command, ffmpeg doesn't start.
This is my command:

ffmpeg -loglevel debug -debug pict -fflags nobuffer -f x11grab -thread_queue_size 1024 -framerate 50 -probesize 42M -i :12 -f alsa -thread_queue_size 1024 -i hw:12,0 -ac 2 -ar 48000 -vf scale=1920:1080,interlace=scan=tff:lowpass=complex -pix_fmt uyvy422 -format_code Hi50 -f decklink -top 1 -flags:v +ildct+ilme -r 25000/1000 'DeckLink Quad (2)'

I'm getting those  errors:

cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
    Last message repeated 1408 times
[rawvideo @ 0x55af0497d140] PACKET SIZE: 8294400, STRIDE: 7680
detected 32 logical cores
[Parsed_scale_0 @ 0x55af0498f840] Setting 'w' to value '1920'
[Parsed_scale_0 @ 0x55af0498f840] Setting 'h' to value '1080'
[Parsed_scale_0 @ 0x55af0498f840] Setting 'flags' to value 'bicubic'
[Parsed_scale_0 @ 0x55af0498f840] w:1920 h:1080 flags:'bicubic' interl:0
[Parsed_interlace_1 @ 0x55af049d1940] Setting 'scan' to value 'tff'
[Parsed_interlace_1 @ 0x55af049d1940] Setting 'lowpass' to value 'complex'
[graph 0 input from stream 0:0 @ 0x55af049d2540] Setting 'video_size' to value '1920x1080'
[graph 0 input from stream 0:0 @ 0x55af049d2540] Setting 'pix_fmt' to value '123'
[graph 0 input from stream 0:0 @ 0x55af049d2540] Setting 'time_base' to value '1/1000000'
[graph 0 input from stream 0:0 @ 0x55af049d2540] Setting 'pixel_aspect' to value '0/1'
[graph 0 input from stream 0:0 @ 0x55af049d2540] Setting 'frame_rate' to value '50/1'
[graph 0 input from stream 0:0 @ 0x55af049d2540] w:1920 h:1080 pixfmt:bgr0 tb:1/1000000 fr:50/1 sar:0/1
[format @ 0x55af049d3540] Setting 'pix_fmts' to value 'uyvy422'
[auto_scaler_0 @ 0x55af049d57c0] Setting 'flags' to value 'bicubic'
[auto_scaler_0 @ 0x55af049d57c0] w:iw h:ih flags:'bicubic' interl:0
[format @ 0x55af049d3540] auto-inserting filter 'auto_scaler_0' between the filter 'Parsed_interlace_1' and the filter 'format'
[AVFilterGraph @ 0x55af049a11c0] query_formats: 5 queried, 3 merged, 1 already done, 0 delayed
[Parsed_scale_0 @ 0x55af0498f840] picking yuv444p out of 25 ref:bgr0 alpha:0
[Parsed_scale_0 @ 0x55af0498f840] w:1920 h:1080 fmt:bgr0 sar:0/1 -> w:1920 h:1080 fmt:yuv444p sar:0/1 flags:0x4
[Parsed_interlace_1 @ 0x55af049d1940] mode:4 filter:complex h:1080 -> h:1080
[auto_scaler_0 @ 0x55af049d57c0] w:1920 h:1080 fmt:yuv444p sar:0/1 -> w:1920 h:1080 fmt:uyvy422 sar:0/1 flags:0x4
cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)

[x11grab @ 0x55af04972740] Thread message queue blocking; consider raising the thread_queue_size option (current value: 1024)
[alsa @ 0x55af0497d580] Thread message queue blocking; consider raising the thread_queue_size option (current value: 1024)
Finishing stream 0:0 without any data written to it.
Finishing stream 0:1 without any data written to it.
[graph_1_in_1_0 @ 0x55af049a8f00] Setting 'time_base' to value '1/48000'
[graph_1_in_1_0 @ 0x55af049a8f00] Setting 'sample_rate' to value '48000'
[graph_1_in_1_0 @ 0x55af049a8f00] Setting 'sample_fmt' to value 's16'
[graph_1_in_1_0 @ 0x55af049a8f00] Setting 'channel_layout' to value '0x3'
[graph_1_in_1_0 @ 0x55af049a8f00] tb:1/48000 samplefmt:s16 samplerate:48000 chlayout:0x3
[format_out_0_1 @ 0x55af049a96c0] Setting 'sample_fmts' to value 's16'
[format_out_0_1 @ 0x55af049a96c0] Setting 'sample_rates' to value '48000'
[format_out_0_1 @ 0x55af049a96c0] Setting 'channel_layouts' to value '0x3'
[AVFilterGraph @ 0x55af049a1100] query_formats: 4 queried, 9 merged, 0 already done, 0 delayed
[decklink @ 0x55af04999f00] Trying to find mode for frame size 1920x1080, frame timing 1/25, field order 2, direction 1, format code (unset)
[decklink @ 0x55af04999f00] Found Decklink mode 1920 x 1080 with rate 25.00(i)
[decklink @ 0x55af04999f00] output: DeckLink Quad (2), preroll: 12, frames buffer size: 24
Output #0, decklink, to 'DeckLink Quad (2)':
  Metadata:
    encoder         : Lavf58.65.101
    Stream #0:0, 0, 1/25: Video: wrapped_avframe, 1 reference frame, uyvy422(top first), 1920x1080 (0x0), 0/1, q=2-31, 200 kb/s, 25 fps, 25 tbn
    Metadata:
      encoder         : Lavc58.119.100 wrapped_avframe
    Stream #0:1, 0, 1/48000: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
    Metadata:
      encoder         : Lavc58.119.100 pcm_s16le
frame=    0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=   0x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Input file #0 (:12):
  Input stream #0:0 (video): 1 packets read (8294400 bytes); 1 frames decoded;
  Total: 1 packets (8294400 bytes) demuxed
Input file #1 (hw:12,0):
  Input stream #1:0 (audio): 0 packets read (0 bytes); 0 frames decoded (0 samples);
  Total: 0 packets (0 bytes) demuxed
Output file #0 (DeckLink Quad (2)):
  Output stream #0:0 (video): 0 frames encoded; 0 packets muxed (0 bytes);
  Output stream #0:1 (audio): 0 frames encoded (0 samples); 0 packets muxed (0 bytes);
  Total: 0 packets (0 bytes) muxed
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)
1 frames successfully decoded, 0 decoding errors

I hope thas someone could help me?

Met vriendelijke groet,
Kind Regards,
Mohammed Abdirahamn
Com1 B.V.
+31 24 7113340 (office)
Kerkenbos 1020i | 6546 BA | Nijmegen | The Netherlands
mohammed.abdirahman at com1.nl<mailto:mohammed.abdirahman at com1.nl>
support at com1.nl<mailto:support at com1.nl>
VAT NL850770427B01 KVK 53152808
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