4
votes
Accepted
How to Create Compatible AVC Video for Muxing Without Re-encode
To concatenate multiple files for expected playback in common players, following properties need to match for
video: codec, codec profile, codec level, resolution, reference count, pixel format, ...
- 32.6k
4
votes
Accepted
Producing small H.264 files with Adobe Media Encoder vs ffmpeg/libx264
Adobe licenses its H.264 encoder from Mainconcept, which doesn't do that well at low bitrates. x264 is pretty much the frontier when it comes at low size output for a given quality target, or quality ...
- 32.6k
4
votes
Accepted
Is CABAC encoding lossy or lossless in ffmpeg?
Cabac is lossless, but h264 is lossy. The part you are missing is that cabac is not THE compression algorithm. It is just the final step out of hundreds of steps in video compression. By the time you ...
- 1,060
2
votes
Accepted
Trim a segment of live, still-encoding H.264/FLV with ffmpeg
Keep FLV but trim using demuxer seek and duration.
ffmpeg -ss 00:00:03.000 -t 00:00:01.000 -i output.flv -c copy output2.mp4
Also, skip -ss if it's 0 i.e. stream start.
- 32.6k
2
votes
Accepted
H.264 adding dark anti-aliasing even on high444 yuv444p
It's a rendering artifact, not an actual error.
See
ffplay test444.mp4 -vf scale=iw*16:-1:flags=neighbor
and
ffmpeg -i test444.mp4 roundtrip.png
You should see no black pixels.
Update: ffplay ...
- 32.6k
2
votes
Accepted
How to calculate the length of the video file that was encoded so far?
Short answer is No.
Longer answer is, it depends.
If you're encoding a file, then generally the output is the duration of the input, unless there's speed change or trim filters or -ss, -to, -t ...
- 32.6k
2
votes
Producing small H.264 files with Adobe Media Encoder vs ffmpeg/libx264
I avoid AME and use x264 via ffmpeg for H.264 encoding. From Premiere I prefer to output a temporary lossless compressed format as the intermediate, such as the free and open-source Ut video, instead ...
- 9,904
1
vote
Accepted
Encoding to the same H.264 size as YouTube
I was able to produce the same size as Youtube by varying the qp option for x264. The value that worked to approximately the same size was qp=20.
- 111
1
vote
I want to convert .mp4 to .ts using H264 at constant framerate 25fps
Do not use ts, use mp4. MPEG-TS (.ts) and mkv default to VFR, while mp4 defaults to cfr. https://trac.ffmpeg.org/wiki/ChangingFrameRate
That is this bug. https://trac.ffmpeg.org/ticket/4768
1
vote
Re-encoding Lossy formats with Lossless formats
You have a fundamental misunderstanding of how lossy compression works. It doesn't throw away information so much as ignore the portions of the image that don't conform to the patterns it is looking ...
- 19.3k
1
vote
encoding 4:2:2 in 10-bit with libx264
I downloaded the ffmpeg from the link
https://sourceforge.net/projects/ffmpeg-hi/?source=typ_redirect
And entered the below command to create 4:2:2 10bit h.264 file:
ffmpeg-hi10-heaac.exe -i "im....
- 11
1
vote
Accepted
I scaled down a video, but the bit rate does not change
The scale filter has no effect on the encoder's bitrate control.
Yes, a scaled down video should have a lower bitrate if it is encoded with the same encoder settings as the source. In your command, ...
- 32.6k
1
vote
Accepted
What does it mean when encode a yuv422 file to yuv420 by libx264 lossless encoding?
To directly compare the YUV422P AVI and YUV420P MP4,
ffmpeg -i input.avi -i out.mp4
-filter_complex
"[0]format=yuv420p,split[avi-p][avi-s];
[1][avi-p]psnr;[1][avi-s]ssim" -f null -
- 32.6k
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