Best Intermediate Edit CODEC for Phone Video?

maxotics · December 13, 2022, 4:24pm

The first problem with the video that comes out of my Samsung S22 Ultra phone (BTW, amazing camera, shoots both front and back separately) is that it’s variable frame rate. I’d rather transcode outside Shotcut. I find Shutter Encoder strikes the right balance, but I can use ffmpeg directly, or am open to other suggestions.

Anyway, what is the best intermediate CODEC that would put the least amount of strain on Shotcut (that is fast scrubbing, etc). From reading other posts it seems DNxHR might be the best? But figured I’d ask.

Again, if you’re doing a silly youtube video using cell phone type footage was is the best edit CODEC (transcode) to put the footage through. Thanks!!!

Austin · December 13, 2022, 5:02pm

DNxHR is usually ideal. So is ProRes, but ProRes will be a significantly larger file since it is 10-bit, but Shotcut won’t take advantage of it since Shotcut is 8-bit.

The Convert to Edit-Friendly feature in Shotcut actually uses FFmpeg for the conversion. The command line can be reverse engineered from the source shown below. The key is the -profile:v dnxhr_hq parameter to get DNxHR.

Since cell phone video quality tends to be a bit low in terms of color tonality anyway, the H.264 All-Intra option is generally sufficient too, with smaller file sizes than DNxHR. If your computer has many cores, the decoder threads extremely well and scrubs fast.

Basically, do a bake-off between H.264 CRF 16 and DNxHR HQ to see what works best for your specific hardware. Core count and base clock frequency are big factors in determining what works best.

github.com

mltframework/shotcut/blob/1c8a0557296dc8024e41d50f5994dee8dd343ec9/src/widgets/avformatproducerwidget.cpp#L811

      
        
                    basename = QString();
                }
                for (unsigned i = 1; i < std::numeric_limits<unsigned>::max(); i++) {
                    QString filename = QString::fromLatin1("%1%2.%3").arg(basename).arg(i).arg(extension);
                    if (!info.dir().exists(filename))
                        return info.dir().filePath(filename);
                }
                return filePath;
            }
            
            
void AvformatProducerWidget::convert(TranscodeDialog &dialog)
            {
                int result = dialog.exec();
                if (dialog.isCheckBoxChecked()) {
                    Settings.setShowConvertClipDialog(false);
                }
                if (result == QDialog::Accepted) {
                    QString resource = Util::GetFilenameFromProducer(producer());
                    QString path = Settings.savePath();
                    QStringList args;
                    QString nameFilter;

maxotics · December 13, 2022, 7:41pm

Hi, thanks! I did the tests you suggested. The DNxHR not only encodes quickly but it seems to scrub much better than the H.264 GOP 1. (setting for that below if I missed something). So unless someone argues differently I believe your suggestion of DNxHR is the best (I also like that it does NOT have a lot of options to scratch my head over)

Here is the DNxHR in Shutter:

system · March 13, 2023, 4:24pm

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