I have a webm video that was made (from an h264) using AWS Elastic Transcoder, using the "System preset: Webm VP9 720p" preset.
For this file, ffprobe gives:
$ ffprobe converted-mp4.webm <snip> Input #0, matroska,webm, from 'converted-mp4.webm': Metadata: title : 1024 x 768 30 fps Photo JPEG 75% - https://archive.org/details/VideoTestFiles encoder : Lavf57.71.100 Duration: 00:00:16.00, start: 0.000000, bitrate: 743 kb/s Stream #0:0: Video: vp9 (Profile 0), yuv420p(tv, progressive), 640x480, SAR 1:1 DAR 4:3, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
yuv420p(tv, progressive) in the last line.
I am trying to replicate as best I can the same encoding using
ffmpeg, but I cannot workout how to get the
$ ffmpeg -i 1024X76830FpsPhotoJpeg75.mp4 -pix_fmt yuva420p -c:v libvpx-vp9 video.webm ... $ ffprobe video.webm <snip> Input #0, matroska,webm, from 'video.webm': Metadata: title : 1024 x 768 30 fps Photo JPEG 75% - https://archive.org/details/VideoTestFiles COMMENT : license:http://creativecommons.org/licenses/by/4.0/ MAJOR_BRAND : isom MINOR_VERSION : 512 COMPATIBLE_BRANDS: isomiso2avc1mp41 ENCODER : Lavf58.20.100 Duration: 00:00:16.00, start: 0.000000, bitrate: 158 kb/s Stream #0:0: Video: vp9 (Profile 0), yuv420p(tv), 640x480, SAR 1:1 DAR 4:3, 30 fps, 30 tbr, 1k tbn, 1k tbc (default) Metadata: alpha_mode : 1 HANDLER_NAME : VideoHandler ENCODER : Lavc58.35.100 libvpx-vp9 DURATION : 00:00:16.000000000
For context, I am trying to work out why the AWS Elastic Transcoder produced file is behaving properly in some downstream processing (either rendering frame-by-frame in a browser, or another encoding/conversion step). In the ffmpeg version, frames are being duplicated/repeated.
For what it's worth, I have tried messing with the key-frame interval (AWS version has key-frame every 90 frames) but that didn't make a difference.
progressive or not property is one difference I can find between the two files. There's also the encoder version but not sure how that would cause the different behaviour`.
Edit: this property is not what's causing my downstream issues, nevertheless, I'd be interested to know more about it.