title: FFMPEG keeping quality when reducing FPS and streaming over RTSP with rtsp-simple-server
body: <p>I'm using the rtsp-simple-server (<a href="https://github.com/aler9/rtsp-simple-server" rel="nofollow noreferrer">https://github.com/aler9/rtsp-simple-server</a>) and feed the RTSP Server with a FFMPEG stream.</p>
  <p>I use a docker compose file to start the stream:</p>
  <pre><code>version: &quot;3.8&quot;
  
  services:
  
    ffmpeg:
      container_name: ffmpeg-base
      restart: always
      image: &quot;jenssgb/rtspffmpeg:base&quot;
      depends_on:
        - rtsp-server
      volumes:
        - $PWD/:/video
      network_mode: &quot;host&quot;
      command: &quot;ffmpeg -re -stream_loop -1 -i /video/footage-1-b.mp4 -c copy -f rtsp rtsp://localhost:8554/compose-rtsp&quot;
    
    rtsp-server:
      container_name: rtsp-server-base
      restart: always
      image: &quot;aler9/rtsp-simple-server&quot;
      network_mode: &quot;host&quot;
  </code></pre>
  <p>Now I'm trying to reduce the FPS of my video with transcoding it:</p>
  <pre><code>command: -re -stream_loop -1 -i ${VIDEO_FILE} -vf &quot;fps=${FPS_COMPOSE}&quot; -f rtsp rtsp://localhost:8554/compose-rtsp
  </code></pre>
  <p>This is basically working, <strong>but the quality of the output video becomes pretty bad</strong>. I tried a lot of things like <code>-c:v libx264</code> which did help for a minute but let ffmpeg crash then.</p>
  <pre><code>av_interleaved_write_frame(): Broken pipe0:00:09.99 bitrate=N/A speed=0.985x    
  [rtsp @ 0x5563b1755640] Packets poorly interleaved, failed to avoid negative timestamp -33660 in stream 0.
  Try -max_interleave_delta 0 as a possible workaround.
  av_interleaved_write_frame(): Broken pipe
  Error writing trailer of rtsp://localhost:8554/compose-rtsp: Broken pipe
  </code></pre>
  <p>Any idea how I can reduce the FPS send the stream to the server but keep the video quality? Later I'm going to reduce the resolution as well - but for now I want to keep resolution and quality but only reduce the FPS.</p>
  <p>Full logs from my test with <code>-c:v libx264</code>:</p>
  <pre><code>    ffmpeg -re -stream_loop -1 -i footage-1-b.mp4 -vf &quot;fps=5&quot; -c:v libx264 -f rtsp rtsp://localhost:8554/compose-rtsp
  ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
    built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
    configuration: --prefix=/usr --extra-version=1ubuntu0.1 --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-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
    libavutil      56. 31.100 / 56. 31.100
    libavcodec     58. 54.100 / 58. 54.100
    libavformat    58. 29.100 / 58. 29.100
    libavdevice    58.  8.100 / 58.  8.100
    libavfilter     7. 57.100 /  7. 57.100
    libavresample   4.  0.  0 /  4.  0.  0
    libswscale      5.  5.100 /  5.  5.100
    libswresample   3.  5.100 /  3.  5.100
    libpostproc    55.  5.100 / 55.  5.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'footage-1-b.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      title           : Session streamed by &quot;nessyMediaServer&quot;
      encoder         : Lavf58.29.100
      comment         : h264_3
    Duration: 00:59:59.63, start: 0.000000, bitrate: 2099 kb/s
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuvj420p(pc), 1280x720 [SAR 1:1 DAR 16:9], 2061 kb/s, 24.96 fps, 25 tbr, 12800 tbn, 25 tbc (default)
      Metadata:
        handler_name    : VideoHandler
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 8000 Hz, mono, fltp, 35 kb/s (default)
      Metadata:
        handler_name    : SoundHandler
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (h264 (native) -&gt; h264 (libx264))
    Stream #0:1 -&gt; #0:1 (aac (native) -&gt; aac (native))
  Press [q] to stop, [?] for help
  [aac @ 0x56277bc7f840] Too many bits 8832.000000 &gt; 6144 per frame requested, clamping to max
  [libx264 @ 0x56277bbc33c0] using SAR=1/1
  [libx264 @ 0x56277bbc33c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
  [libx264 @ 0x56277bbc33c0] profile High, level 3.1
  [libx264 @ 0x56277bbc33c0] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - 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=12 lookahead_threads=2 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=5 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, rtsp, to 'rtsp://localhost:8554/compose-rtsp':
    Metadata:
      major_brand     : isom
      minor_version   : 512
      compatible_brands: isomiso2avc1mp41
      title           : Session streamed by &quot;nessyMediaServer&quot;
      comment         : h264_3
      encoder         : Lavf58.29.100
      Stream #0:0(und): Video: h264 (libx264), yuvj420p(pc), 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 5 fps, 90k tbn, 5 tbc (default)
      Metadata:
        handler_name    : VideoHandler
        encoder         : Lavc58.54.100 libx264
      Side data:
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
      Stream #0:1(und): Audio: aac (LC), 8000 Hz, mono, fltp, 48 kb/s (default)
      Metadata:
        handler_name    : SoundHandler
        encoder         : Lavc58.54.100 aac
  av_interleaved_write_frame(): Broken pipe0:00:09.87 bitrate=N/A speed=0.978x    
  [rtsp @ 0x56277bba0640] Packets poorly interleaved, failed to avoid negative timestamp -33660 in stream 0.
  Try -max_interleave_delta 0 as a possible workaround.
  av_interleaved_write_frame(): Broken pipe
  Error writing trailer of rtsp://localhost:8554/compose-rtsp: Broken pipe
  frame=   50 fps=4.6 q=23.0 Lsize=N/A time=00:00:10.21 bitrate=N/A speed=0.947x    
  video:162kB audio:8kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  [libx264 @ 0x56277bbc33c0] frame I:1     Avg QP:19.85  size:165667
  [libx264 @ 0x56277bbc33c0] frame P:13    Avg QP:20.88  size:140481
  [libx264 @ 0x56277bbc33c0] frame B:36    Avg QP:24.58  size: 55445
  [libx264 @ 0x56277bbc33c0] consecutive B-frames:  4.0%  0.0%  0.0% 96.0%
  [libx264 @ 0x56277bbc33c0] mb I  I16..4:  4.4% 30.8% 64.8%
  [libx264 @ 0x56277bbc33c0] mb P  I16..4:  4.1% 10.6% 20.0%  P16..4: 24.4% 24.8% 13.3%  0.0%  0.0%    skip: 2.6%
  [libx264 @ 0x56277bbc33c0] mb B  I16..4:  0.8%  2.0%  4.0%  B16..8: 40.3% 14.5%  5.2%  direct:11.8%  skip:21.4%  L0:77.1% L1: 7.9% BI:14.9%
  [libx264 @ 0x56277bbc33c0] 8x8 transform intra:30.1% inter:11.9%
  [libx264 @ 0x56277bbc33c0] coded y,uvDC,uvAC intra: 82.5% 60.9% 26.6% inter: 55.0% 42.4% 2.7%
  [libx264 @ 0x56277bbc33c0] i16 v,h,dc,p: 17% 26% 34% 23%
  [libx264 @ 0x56277bbc33c0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 33% 15%  3%  4%  5%  4%  3%  9%
  [libx264 @ 0x56277bbc33c0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 20% 22% 13%  3% 17% 11%  5%  3%  6%
  [libx264 @ 0x56277bbc33c0] i8c dc,h,v,p: 54% 25% 16%  5%
  [libx264 @ 0x56277bbc33c0] Weighted P-Frames: Y:7.7% UV:7.7%
  [libx264 @ 0x56277bbc33c0] ref P L0: 33.2% 11.6% 29.0% 23.9%  2.4%
  [libx264 @ 0x56277bbc33c0] ref B L0: 79.6% 11.9%  8.5%
  [libx264 @ 0x56277bbc33c0] ref B L1: 95.9%  4.1%
  [libx264 @ 0x56277bbc33c0] kb/s:3190.34
  [aac @ 0x56277bc7f840] Qavg: 65536.000
  Conversion failed!
  </code></pre>
  <p>Thank you,
  J</p>