[FFmpeg-user] Reducing image2pipe png decoder latency

[Maxim Khitrov]

On Wed, Dec 11, 2019 at 9:42 AM Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> There is something strange about your console output (many lines
> seem to be missing), if this is a patched binary of FFmpeg, please
> ask for support wherever you found the binary.
>
> Carl Eugen

I'm using ffmpeg-20191211-4110029-win64-static binary from
ffmpeg.zeranoe.com/builds/. Here's the verbose output:

[image2pipe @ 00000275256eefc0] Stream #0: not enough frames to
estimate rate; consider increasing probesize
Input #0, image2pipe, from '\\.\pipe\ffmpeg-fjTn1bOtYSpsze3Q.0':
  Duration: N/A, start: 1576092972.633333, bitrate: N/A
    Stream #0:0: Video: mjpeg, 1 reference frame,
yuvj420p(bt470bg/unknown/unknown, center), 1280x720, 30 tbr, 30 tbn,
30 tbc
[image2pipe @ 00000275256f4440] Stream #0: not enough frames to
estimate rate; consider increasing probesize
Input #1, image2pipe, from '\\.\pipe\ffmpeg-fjTn1bOtYSpsze3Q.1':
  Duration: N/A, start: 1576092972.633333, bitrate: N/A
    Stream #1:0: Video: png, 1 reference frame, rgba(pc), 640x360, 30
tbr, 30 tbn, 30 tbc
[Parsed_scale2ref_0 @ 0000027525717b80] w:iw h:ih flags:'bilinear' interl:0
Stream mapping:
  Stream #0:0 (mjpeg) -> scale2ref:ref
  Stream #1:0 (png) -> scale2ref:default
  overlay -> Stream #0:0 (libx264)
[Parsed_scale2ref_0 @ 000002752572fcc0] w:iw h:ih flags:'bilinear' interl:0
[graph 0 input from stream 1:0 @ 0000027525755840] w:640 h:360
pixfmt:rgba tb:1/30 fr:30/1 sar:0/1 sws_param:flags=2
[graph 0 input from stream 0:0 @ 0000027525755940] w:1280 h:720
pixfmt:yuvj420p tb:1/30 fr:30/1 sar:0/1 sws_param:flags=2
[Parsed_scale2ref_0 @ 000002752572fcc0] w:1280 h:720 fmt:yuvj420p
sar:0/1 -> w:1280 h:720 fmt:yuva420p sar:0/1 flags:0x2
[Parsed_overlay_1 @ 000002752572b980] x:0.000000 xi:0 y:0.000000 yi:0
[Parsed_overlay_1 @ 000002752572b980] main w:1280 h:720 fmt:yuvj420p
overlay w:1280 h:720 fmt:yuva420p
[Parsed_overlay_1 @ 000002752572b980] [framesync @ 00000275257565e8]
Selected 1/30 time base
[Parsed_overlay_1 @ 000002752572b980] [framesync @ 00000275257565e8]
Sync level 2
[libx264 @ 00000275256f71c0] using cpu capabilities: MMX2 SSE2Fast
SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 00000275256f71c0] profile High, level 3.1, 4:2:0, 8-bit
[mpegts @ 00000275256f4f40] service 1 using PCR in pid=256, pcr_period=100ms
[mpegts @ 00000275256f4f40] muxrate VBR, sdt every 500 ms, pat/pmt every 100 ms
Output #0, mpegts, to 'pipe:':
  Metadata:
    encoder         : Lavf58.35.101
    Stream #0:0: Video: h264 (libx264), 1 reference frame,
yuvj420p(pc), 1280x720, q=-1--1, 30 fps, 90k tbn, 30 tbc (default)
    Metadata:
      encoder         : Lavc58.64.101 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
[Parsed_overlay_1 @ 000002752572b980] [framesync @ 00000275257565e8]
Sync level 1 speed=0.973x
[Parsed_overlay_1 @ 000002752572b980] [framesync @ 00000275257565e8]
Sync level 0
No more output streams to write to, finishing.
frame=  241 fps= 30 q=22.0 Lsize=    1296kB time=00:00:08.00
bitrate=1326.9kbits/s speed=   1x
video:1209kB audio:0kB subtitle:0kB other streams:0kB global
headers:0kB muxing overhead: 7.180827%
Input file #0 (\\.\pipe\ffmpeg-fjTn1bOtYSpsze3Q.0):
  Input stream #0:0 (video): 240 packets read (5200330 bytes); 240
frames decoded;
  Total: 240 packets (5200330 bytes) demuxed
Input file #1 (\\.\pipe\ffmpeg-fjTn1bOtYSpsze3Q.1):
  Input stream #1:0 (video): 240 packets read (657386 bytes); 240
frames decoded;
  Total: 240 packets (657386 bytes) demuxed
Output file #0 (pipe:):
  Output stream #0:0 (video): 241 frames encoded; 241 packets muxed
(1238005 bytes);
  Total: 241 packets (1238005 bytes) muxed
[AVIOContext @ 00000275256f7f80] Statistics: 0 seeks, 241 writeouts
[libx264 @ 00000275256f71c0] frame I:1     Avg QP: 5.37  size:  8448
[libx264 @ 00000275256f71c0] frame P:240   Avg QP: 8.85  size:  5123
[libx264 @ 00000275256f71c0] mb I  I16..4: 93.3%  0.1%  6.6%
[libx264 @ 00000275256f71c0] mb P  I16..4: 83.3%  1.5%  1.3%  P16..4:
6.6%  0.0%  0.0%  0.0%  0.0%    skip: 7.3%
[libx264 @ 00000275256f71c0] 8x8 transform intra:1.7% inter:93.2%
[libx264 @ 00000275256f71c0] coded y,uvDC,uvAC intra: 1.5% 4.4% 3.1%
inter: 27.8% 34.2% 3.5%
[libx264 @ 00000275256f71c0] i16 v,h,dc,p: 78% 11% 10%  0%
[libx264 @ 00000275256f71c0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  3%  5%
46% 40%  0%  0%  0%  0%  5%
[libx264 @ 00000275256f71c0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 62% 19%
13%  1%  1%  1%  1%  1%  1%
[libx264 @ 00000275256f71c0] i8c dc,h,v,p: 72% 12% 15%  0%
[libx264 @ 00000275256f71c0] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 00000275256f71c0] kb/s:1232.87
[AVIOContext @ 00000275256fa340] Statistics: 5243794 bytes read, 1 seeks
[AVIOContext @ 0000027525723d00] Statistics: 661981 bytes read, 1 seeks