I've successfully managed to extract OCR data from frames using ffprobe with the following command:
ffprobe -loglevel quiet -hide_banner -select_streams v:0 -show_entries frame_tags=lavfi.ocr.text -f lavfi "movie=movie.mov,ocr" -of flat
It neatly outputs the info on one line like this:
frames.frame.0.tags.lavfi_ocr_text="EE 6:\n_ 00:59:35.00\n"
frames.frame.1.tags.lavfi_ocr_text="ET =:\na Clo Koy\n"
frames.frame.2.tags.lavfi_ocr_text="EE =:\na loony\n"
frames.frame.3.tags.lavfi_ocr_text="=:\na 00:59:35.03\n"
frames.frame.4.tags.lavfi_ocr_text="U6:\na 00:59:35.04\n"
frames.frame.5.tags.lavfi_ocr_text="6:\nal 00:59:35.05\n"
frames.frame.6.tags.lavfi_ocr_text="EE Zz:\nim 00:59:35.06\n"
frames.frame.7.tags.lavfi_ocr_text="=:\nim ll¢kosc hc Lon OYA\n"
frames.frame.8.tags.lavfi_ocr_text="=:\nim 00:59:35.08\n"
frames.frame.9.tags.lavfi_ocr_text="Zz:\nim 00:59:35.09\n"
frames.frame.10.tags.lavfi_ocr_text="=:\nim 00:59:35.10\n"
However, since scanning each frame is a resource intensive operation and depending on how much text is on screen it can sometimes take several seconds per frame I created another probe to detect the first (almost) completely black frame:
ffprobe -loglevel quiet -hide_banner -select_stream v:0 -show_entries frame_tags=lavfi.blackframe.pblack -f lavfi "movie=movie.mov,blackframe" -of flat | head -n1
This command outputs the following:
frames.frame.240.tags.lavfi_blackframe_pblack="99"
I managed to strip off all the stuff except for the "240" number I need. What I want now is to use this number to offset the starting frame for the first command so that its output will start on that frame like this:
frames.frame.240.tags.lavfi_ocr_text="EE 6:\n_ 00:59:35.00\n"
frames.frame.241.tags.lavfi_ocr_text="ET =:\na Clo Koy\n"
frames.frame.242.tags.lavfi_ocr_text="EE =:\na loony\n"
frames.frame.243.tags.lavfi_ocr_text="=:\na 00:59:35.03\n"
frames.frame.244.tags.lavfi_ocr_text="U6:\na 00:59:35.04\n"
frames.frame.245.tags.lavfi_ocr_text="6:\nal 00:59:35.05\n"
frames.frame.246.tags.lavfi_ocr_text="EE Zz:\nim 00:59:35.06\n"
frames.frame.247.tags.lavfi_ocr_text="=:\nim ll¢kosc hc Lon OYA\n"
frames.frame.248.tags.lavfi_ocr_text="=:\nim 00:59:35.08\n"
frames.frame.249.tags.lavfi_ocr_text="Zz:\nim 00:59:35.09\n"
frames.frame.250.tags.lavfi_ocr_text="=:\nim 00:59:35.10\n"
I've already tried creating JPG's with ffmpeg that I can then use with ffprobe but this means creating temp files and stuff. I want to prevent this if possible. I also looked at the -read_intervals option but this doesn't seem to work at all.
I'm running macOS Mojave 10.14.3 with ffprobe:
ffprobe version 4.1.1 Copyright (c) 2007-2019 the FFmpeg developers
built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)
configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/openjdk-11.0.2.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/openjdk-11.0.2.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
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
Simple multimedia streams analyzer
usage: ffprobe [OPTIONS] [INPUT_FILE]
Can what I want be done using ffprobe alone?