62 lines
2.2 KiB
Markdown
62 lines
2.2 KiB
Markdown
# Creating Test Content
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## Table of Contents
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- [CEA-608 Content](#creating-cea-608-content)
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## Creating CEA-608 Content
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- Use ffmpeg to create an MP4 file to start with:
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`ffmpeg -f lavfi -i testsrc=duration=300:size=1280x720:rate=30 -profile:v baseline -pix_fmt yuv420p output.mp4` (no audio)
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`ffmpeg -f lavfi -i testsrc=duration=300:size=1280x720:rate=30 -profile:v baseline -pix_fmt yuv420p -filter_complex "anoisesrc=d=300" output.mp4` (audio + video)
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This uses ffmpeg's built-in `testsrc` source which generates a test video pattern with a color and timestamp. For this example, we are using a duration of `300` seconds, a size of `1280x720` and a framerate of `30fps`. We also specify extra settings `profile` and `pix_fmt` to force the output to be encoded using `avc1.42C01F`.
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- Create an [srt file][srt] with the captions you would like to see with their timestamps.
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- Use ffmpeg to convert `ouput.mp4` to a flv file:
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`ffmpeg -i output.mp4 -acodec copy -vcodec copy output.flv`
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- Use [libcaption][] to embed the captions into the flv:
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`flv+srt output.flv captions.srt with-captions.flv`
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- Use ffmpeg to convert `with-captions.flv` to mp4
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`ffmpeg -i with-captions.flv -acodec copy -vcodec copy with-captions.mp4`
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- Use [Bento4][bento4] to convert the file into a FMP4 file:
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`bento4 mp4fragment with-captions.mp4 \
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--verbosity 3 \
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--fragment-duration 4000 \
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--timescale 90000 \
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with-captions-fragment.mf4`
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Then do *either* of the following:
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- Use [Bento4][bento4] to split the file into an init segment and a fmp4 media segments:
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`bento4 mp4split --verbose \
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--init-segment with-captions-init.mp4 \
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--media-segment segs/with-captions-segment-%llu.m4s \
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with-captions-fragment.mf4`
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- Use [Bento4][bento4] to create a DASH manifest:
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`bento4 mp4dash -v \
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--mpd-name=with-captions.mpd \
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--init-segment=with-captions-init.mp4 \
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--subtitles
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with-captions-fragment.mf4`
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This will create a DASH MPD and media segments in a new directory called `output`.
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[srt]: https://en.wikipedia.org/wiki/SubRip#SubRip_text_file_format
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[libcaption]: https://github.com/szatmary/libcaption
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[bento4]: https://www.bento4.com/documentation/
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