The doding of packets of a video stream does not yield all the frames.

Created by: g-kartik

IMPORTANT: Be sure to replace all template sections {{ like this }} or your issue may be discarded.

Overview

{{ The number of frames decoded from the packets of a video stream is one less than total number of actual frames }}

Expected behavior

{{ Decoding of video stream packets should yield all frames and should not miss any }}

Actual behavior

{{ One frame is missing while decoding frames of the video stream }}

Traceback:

{{ Include complete tracebacks if there are any exceptions. }}

Investigation

Reproduction

{{ `container = av.open('any_video.mp4, mode='r')

frame_count = 0 for packet in container.demux(video=0): for frame in packet.decode(): frame_count += 1

original_frame_count = container.streams.video[0].frames

assert original_frame_count == frame_count + 1 ` }}

Versions

OS: {{ e.g. manjaro 21.2.6 }}
PyAV runtime: 9.2.0

{{ PyAV v9.2.0
library configuration: --disable-static --enable-shared --libdir=/tmp/vendor/lib --prefix=/tmp/vendor --disable-alsa --disable-doc --disable-mediafoundation --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-lzma --enable-version3 --enable-zlib
library license: GPL version 3 or later
libavcodec     58.134.100
libavdevice    58. 13.100
libavfilter     7.110.100
libavformat    58. 76.100
libavutil      56. 70.100
libswresample   3.  9.100
libswscale      5.  9.100
 }}

PyAV build:

{{ Complete output of `python setup.py config --verbose`. }}

FFmpeg:

{{ ffmpeg version n5.0 Copyright (c) 2000-2022 the FFmpeg developers
built with gcc 11.2.0 (GCC)
configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-amf --enable-avisynth --enable-cuda-llvm --enable-lto --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmfx --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librav1e --enable-librsvg --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-libzimg --enable-nvdec --enable-nvenc --enable-shared --enable-version3
libavutil      57. 17.100 / 57. 17.100
libavcodec     59. 18.100 / 59. 18.100
libavformat    59. 16.100 / 59. 16.100
libavdevice    59.  4.100 / 59.  4.100
libavfilter     8. 24.100 /  8. 24.100
libswscale      6.  4.100 /  6.  4.100
libswresample   4.  3.100 /  4.  3.100
libpostproc    56.  3.100 / 56.  3.100 }}

Research

I have done the following:

Checked the PyAV documentation
Searched on Google
Searched on Stack Overflow
Looked through old GitHub issues
Asked on PyAV Gitter
... and waited 72 hours for a response.