"Encrypted email is LARP security"

Latacora: Stop Using Encrypted Email

Most email encryption on the Internet is performative, done as a status signal or show of solidarity. Ordinary people don't exchange email messages that any powerful adversary would bother to read, and for those people, encrypted email is LARP security. It doesn't matter whether or not these emails are safe, which is why they're encrypted so shoddily. [...]

Every long term secret will eventually leak. [...] Different tools do better and worse jobs of forward secrecy, but nothing does worse than encrypted Internet email, which not only demands of users that they keep a single long-term key, but begs them to publish those keys in public ledgers. Every new device a user of these systems buys and every backup they take is another opportunity for total compromise. Users are encouraged to rotate their PGP keys in the same way that LARPers are encouraged to sharpen their play swords: not only does nobody do it, but the whole system would probably fall apart if everyone did.

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ffmpeg frame rate weirdness

Dear Lazyweb, can you explain to me why concatenating two 30fps video files results in a 29.72fps video file, and how to avoid it?

% ffmpeg -i example1.ts 2>&1 | grep fps
Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 640x360 [SAR 1:1 DAR 16:9], 30 fps, 30 tbr, 90k tbn, 60 tbc

% ffmpeg -i example2.ts 2>&1 | grep fps
Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 640x360 [SAR 1:1 DAR 16:9], 30 fps, 30 tbr, 90k tbn, 60 tbc

% (echo file example1.ts; echo file example2.ts) > list.txt
% ffmpeg -hide_banner -v 16 -f concat -i list.txt -codec copy example3.mp4

% ffmpeg -i example3.mp4 2>&1 | grep fps
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360 [SAR 1:1 DAR 16:9], 493 kb/s, 29.72 fps, 30 tbr, 90k tbn, 60 tbc (default)

Transcoding it gets me 30fps, but since both started at 30fps, why doesn't copying work?

% ffmpeg -hide_banner -v 16 -f concat -i list.txt -c:v libx264 -profile:v high -crf 28 -pix_fmt yuv420p -acodec libfdk_aac -b:a 192k -r 30 -movflags faststart example4.mp4
% ffmpeg -i example4.mp4 2>&1 | grep fps

Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360 [SAR 1:1 DAR 16:9], 449 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)

Previously.

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