Create thumbnails

Generate the deterministic practice fixture before running this recipe:

python tests/media/download_fixtures.py --force

Create a 640-pixel-wide JPEG thumbnail and save both a machine-readable result and a privacy-redacted receipt:

pyffmpegcore thumbnail \
    --input tests/media/downloads/sample_mp4_h264.mp4 \
    --output thumbnail.jpg \
    --timestamp 00:00:01 \
    --width 640 \
    --receipt thumbnail.receipt.json \
    --result-json > thumbnail.result.json

The result JSON proves that the command succeeded. Use the separate probe command to obtain machine-readable proof of the image codec and requested width:

pyffmpegcore probe --input thumbnail.jpg --json

The output should report mjpeg for video.codec and 640 for video.width. The same facts are available in the receipt at items[0].output_probe.streams[0].codec and items[0].output_probe.streams[0].width.

Validate the redacted receipt without accessing the media again:

pyffmpegcore receipt validate thumbnail.receipt.json --json

The validation result should contain "valid": true.

The requested timestamp must exist in the source. Supplying both width and height forces those dimensions; supplying one preserves the aspect ratio according to FFmpeg scale rules.

The CLI refuses to overwrite an existing thumbnail or receipt by default. Run the command again with --force when replacement is intentional:

pyffmpegcore thumbnail \
    --input tests/media/downloads/sample_mp4_h264.mp4 \
    --output thumbnail.jpg \
    --timestamp 00:00:01 \
    --width 640 \
    --receipt thumbnail.receipt.json \
    --force

For a synthetic input that is safe to share in a bug report:

pyffmpegcore smoke-test --keep-dir synthetic-demo

That command already verifies the generated thumbnail with FFprobe.