I have a problem when libx264 I-Vstats do not get all the frame information in the encoding of a YUV using FMPPG Production. It raises the question that what is reliable ffmpeg, and therefore, can any review on the basis of any 'codec benchmark' FFPAP be reliable?
I am analyzing the codec to decide how they do it. I am using the ffmpeg and its-vstats option to view an encoded film frame by frame. Process to be used:
RAU YUV -> Bar-code with each frame frame number -> bar-coded YUV
bar-coded YUV -> encoded (e.g. For libx264) -> MKV -> UOV decoded
I can compare two outputs ('bar-coded YUV' and 'decoded to YUV') using bar-code in each frame I am Then I can compare an original frame using an encoded frame using PSNR etc.
When libx264 and libdirac are used by encoding, then some frame information that is unavailable is not available to other codecs, such as MPEG2 video or even libvpx, to this problem.
I've found that for the first 40 to 50 frames the libx264 vstats are unavailable. I have since proven that the missing information is actually the last 40 to 50 frames
It also shows that ffmpeg calculates the average bitrate based on the information in vstats. But since the frame is not missing the average bitrate is less than what it should do.
Below are the links of average bitrate error examples:
Below is a link for PSNR & amp; F_size graph:
Below is a link to output & amp; Command line option:
I think it is also a bug that is enough to work, you might want to follow this tracker:
I found something that makes me look very red in the face !! Quite annoying, but never mind :)
A fellow FFMPEN user told that the FFprobe should be made more framed, which he did. Here is a link to their work tip:
By using it I found the following:
Actual average bitrate (FFprobe data): 8355.2776056338
Actual average bitrate (ffmpeg vstats data): 8406.23275471698
Ffmpeg -vstats avg_br: 7816.3
Product: 7816.32168421053
Ffmpeg standard error output 'bitrate =': 8365.8
Below a link My workings:
I have come to know that I should have used average bitrate information from FFPAG standard error output, Looks the most reliable!
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