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7 votes

restart ffmpeg job from failure

A direct option to resume encoding is not available. And as for manually restarting encoding, that's also not possible. Two reasons: 1) when transcoding to a typical container like MP4, the index is ...
Gyan's user avatar
  • 33.3k
6 votes
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ffmpeg transcoding H264 interlaced and keep interlacing via H264_NVENC codec

It's an issue with new video drivers. Everything is fine with video driver 361.28 and lower. I already sent this issue to NVIDIA Support with Reference Number 161118-000164 UPDATE: This issue has ...
Ivan Kolesnikov's user avatar
5 votes

Why when you specify a video bitrate with ffmpeg does the resulting files displayed bit rate differ?

The issue is that you are using -crf with -b:v. ffmpeg is a well built program, so it's just ignoring -b:v and using -crf. If you want to have a specific bitrate, remove the crf command. CRF is "...
user3643's user avatar
  • 2,264
5 votes
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RTSP to RTMP converting fails after specific time only when IP camera enters night mode

I've solved the issue by rebuilding the timestamps from scratch with -use_wallclock_as_timestamps 1 and -fflags +genpts. /usr/bin/ffmpeg -use_wallclock_as_timestamps 1 -i "rtsp://${source}" -fflags +...
mjktfw's user avatar
  • 191
4 votes
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what graphics card features effect NVIDIA NVENC hardware encoding speed?

There are two main features in NVIDIA NVENC encoding: Video memory if you need to transcode many streams. NVENC SIP - than better this SIP than better encoding performance is. It depends on GPU. You ...
Ivan Kolesnikov's user avatar
4 votes
Accepted

Questions on workflow: 12G-SDI to 500Mbps to RTSP stream

I've worked through a similar project over the last 6 months, and performed more tests than I can keep track of now. So this is a little fresh for me. With your questions: 4K camera -> capture ...
hmedia1's user avatar
  • 172
4 votes
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ffmpeg transpose=clock rotates 180 degrees instead 90

FFmpeg, by default, autorotates videos if a rotation tag is detected. The output video will be oriented upright and have no rotation tag. During processing, this step happens before any filtering is ...
Gyan's user avatar
  • 33.3k
4 votes

How to preserve colorspace in ffmpeg

This command preserved the colorspace and also video didnt get darker after transcoding ffmpeg -i input.mp4 -color_primaries smpte170m -color_trc smpte170m -colorspace smpte170m -r 25 -crf 18 output....
mustafa candan's user avatar
3 votes

Converting WMV to MP4

All that matters is if the MP4 looks good to you. Of course, you may be able to compress more. There is no set bitrate to use. More complex or rapidly changing visuals require greater bitrate. Most ...
Gyan's user avatar
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3 votes
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Is there a video container which is able to handle segments of different video quality (or even size)?

If the only difference is bitrate, then any container which accepts variable bitrate streams, will fulfill your requirement e.g. MP4, MKV..etc Step 1 is to encode your segments, ideally using the ...
Gyan's user avatar
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3 votes
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Transcode 5.1 audio in ffmpeg leads to incorrect audio mapping in output

FFmpeg assumes that the input's 5.1 channel mapping is the same as the one it uses. To correct that, use the channelmap filter to remap, add: -af "channelmap=4|0|1|2|3|5:5.1" (I based it off the ...
Gyan's user avatar
  • 33.3k
3 votes

How should I interpret the results from Netflix VMAF

In general, the higher the VMAF score, the higher the quality of the video will be perceived by the viewer. Lower VIF component and ADM scores indicate problems caused by intra-frame compression ...
Michael Liebman's user avatar
3 votes

How should I interpret the results from Netflix VMAF

The VMAF models are actually trained by humans who rated the quality on a 1-5 point scale, watching the movie either on an 1080p screen from 3x screen height away, or on a 4k screen from 1.5x screen ...
stribika's user avatar
  • 211
3 votes

Intra-frame H.264 / H.265 compared to DNxHR or Prores as intermediate codecs for editing

ProRes/CineForm/DNxHR caught on because of the platforms which decided to use them. Initially, H.264 didn't have 10-bit implementations and H.265 didn't exist. Those formats are made to hold up to ...
qel's user avatar
  • 131
3 votes
Accepted

Best strategy to keep aspect ratio consistent for all videos having any resolution

If you want the output resolution to be 1280x720 and the video keeps its original ratio aspect as well: ffmpeg -v error -stats -i input -vf "scale=1280:720:force_original_aspect_ratio=1,pad=1280:720:...
Rami Magdi's user avatar
2 votes
Accepted

FFmpeg transcoding GOP pattern IP

Use ffmpeg -i INPUT -vcodec libx264 -g 2 -acodec copy -y out.mpg As per the x264 docs, scenecut=0 disables scenecut evaluation.
Gyan's user avatar
  • 33.3k
2 votes
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DVD not displaying full picture

You will need to work within the title safe areas when burning to DVD as depending on what the final player will be, there might be overscan which will/can crop anything out that is not within this ...
Adam Mann Pro's user avatar
2 votes

How do I know if a video file is encoded perfectly or not?

There are several methods/algorithms to compare a transcoded file against its original. This is a good article which I believe covers what you're asking. It touches on algorithms such as Peak Signal-...
iangetz's user avatar
  • 121
2 votes
Accepted

Please Explain the Codecs in my Example

So codecs compress and decompress videos, right? COmpress DECompress. Yep. Just like with text encoding, e.g. ascii or unicode, but with video you take a raster (grid of pixels) and turn that into a ...
stib's user avatar
  • 13.7k
2 votes
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Converting to Uncompressed Video Files

The answer to your question depends on the software you will use for editing. Uncompressed RAW video is rarely used for editing for performance reasons. If you have actually recorded your media in 10-...
Tony Sepia's user avatar
2 votes
Accepted

Recover mangled VirtualBox-generated WebM video

After a bit manipulation... You see... Most easiest way for you: Write very simple app in C, which will read 1024*768*3 bytes and pads by zeros to 1327*768*3 bytes. It easy for you. Dump raw pixels ...
bukkojot's user avatar
  • 675
2 votes
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How to make ffmpeg flush the subtitles in real time while transcoding?

When ffmpeg will flush to output depends on the protocol. For file protocol, atleast 256 kiB data must be waiting, unless it's end of output. So, for text formats, there will be only one payload write....
Gyan's user avatar
  • 33.3k
2 votes

How should I interpret the results from Netflix VMAF

The numbers don’t mean anything. They only have value when compared to other values. You can compare the results between two encodes of the same file and determine which encode produced better results....
SlimSCSI's user avatar
  • 1,090
2 votes
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How to choose the right bitrate, H.264 profile and level for Web Video presentation?

If you are looking to get the best possible quality, encode at the highest bitrates you can factoring file size / upload time. Regardless of what you bitrate you transcode at; nearly all streaming ...
McFlySoHigh's user avatar
  • 2,487
2 votes

How to concatenate 2 MP4 videos to output of certain bitrate?

Step 4 (first attempt) will work if you re-encode the 2nd video like the first (without the filters). What's happening is that besides the timescale difference between CC's output and ffmpeg's (which ...
Gyan's user avatar
  • 33.3k
2 votes

If I use a normal build of ffmpeg how take advantage of video acceleration for scale?

The answer to your second question is yes. Change -c:v libx264 to -c:v h264_nvenc. I use those builds as well. If you use the option -encoders you can see a list of included video and audio codecs. ...
Gordon's user avatar
  • 106
2 votes
Accepted

ffmpeg: Preserve timecode when converting mov to mp4

After some detective work, I've started using a command line that converts the video and keeps the timecode intact: ffmpeg -y -i input.mov -map 0:v -map 0:a -c:v mpeg4 output.mp4
DiB's user avatar
  • 141
2 votes

Recommandation for on-premises video file transcoding server accessible via REST API?

Telestream used to make one called FlipFactory that I have used (a long time ago). I believe it's called Vantage now. https://www.telestream.net/vantage/overview.htm A lot of people do this kind of ...
tomh's user avatar
  • 7,908
1 vote

Resolve Transcoding Workflow

Old question, but in Media Management, there should be an option to relink the new footage. This should allow you use the new transcoded footage within the same project. It's under the "+ more ...
FraserHoenes's user avatar
1 vote
Accepted

Simple: Can HTML5 Play a .mpd Manifest File Through Its Video Tag?

Not all browsers and mobile devices natively support MPEG-DASH ( .mpd), DASH is natively supported in Chrome (including Android 4.0+), Internet Explorer 11 on Windows 8.1, and many SmartTVs. To ...
Lea Klein's user avatar
  • 181

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