Search everywhere only in this topic. Advanced Search. Classic List Threaded. Meaning of ffprobe output. Hi, can anybody explain me the data of ffprobe, I don't find enough hints in the docu.
Carl Eugen Hoyos Re: Meaning of ffprobe output. Not necessarily related: "-c copy" cannot change anything about fields "half-frames"libx does not support PAFF encoding. Ulf Zibis. Thanks Carl Eugen Am For what stands 90k? For 90, milli seconds? Anyway, without the flag I get the same ffprobe data. What is PAFF? Hi, Am Do you mean MPEG-2 with "mpeg"? I suspect timebase is a fraction and has no unit but I may be wrong.
What is the ffmpeg option for this? Only old! CRTs can do this, so I assume this has no relevance here. The "idet" filter can do this. Hi again, Am Timebase without unit? What does it serve for? You may be right. Technically I don't see an obstacle for a software player to feed the video display buffer with 50 half-frames per second, as most displays refresh rate is at least 50 per sec.
At least one output file must be specified. Now I'm confused what to do, as I don't want to create another big file. How is the correct syntax?
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Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Is it possible to run ffmpeg from the command line which will either place the 'moov atom' metadata in the beginning of the MP4 file or run the qt-faststart as a post processing operation in ffmpeg so the generated file is stream-able through the internet?
Seems like faststart support has been included in ffmpeg. FFmpeg Formats Documentation :. Run a second pass moving the moov atom on top of the file. This operation can take a while, and will not work in various situations such as fragmented output, thus it is not enabled by default.
Learn more. Post processing in ffmpeg to move 'moov atom' in MP4 files qt-faststart Ask Question. Asked 8 years, 5 months ago. Active 5 years, 7 months ago. Viewed 43k times. If the space reserved is insufficient, muxing will fail. Yes, It is possible to move the moov atom at beginning of the file refer : stackoverflow.
Active Oldest Votes. FFmpeg Formats Documentation : -movflags faststart Run a second pass moving the moov atom on top of the file.
Salman A Salman A k 73 73 gold badges silver badges bronze badges. This worked for me. It does a second pass and then the moov atom is moved to beginning. This worked for me only when I had the -codec:v libx arguments. To support this, I had to configure ffmpeg with the --enable-gpl --enable-libx options.
The web server must support it. Same mechanism as download resuming. Ended up setting up and running qt-faststart after ffmpeg conversion process. This i more aptly a comment rather an answer. Sign up or log in Sign up using Google.
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Video Production Stack Exchange is a question and answer site for engineers, producers, editors, and enthusiasts spanning the fields of video, and media creation. It only takes a minute to sign up. It's impssible — video codec copy means no decoding, no encoding, no filtering - simply copying without any change.
It is not a real codec. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Resize video while live streaming with ffmpeg Ask Question. Asked 7 months ago. Active 7 months ago. Viewed times. I tried this: ffmpeg -re -y -i this.
Can this be done or I am asking the impossible? Active Oldest Votes. Try omitting -vcodec copy to enable FFmpeg to choose an appropriate codec.
MarianD MarianD 1, 2 2 gold badges 8 8 silver badges 23 23 bronze badges. OK thanks. Based on your comments, I was able to resize and to live stream using: ffmpeg -re -i this.
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Formats I must produce are:. I need to create common templates for a couple use cases convert to same-as-source, por p and be able to process these quickly, and en queue.
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Range is logarithmic 0 lossless to 51 worst quality. Default is Use the highest value that still gives you an acceptable quality. If you are re-encoding impractically large inputs to upload to YouTube or similar then try a value of 17 or 18 since these video services will re-encode anyway.
A slower preset provides better compression quality per file size but is slower. Use the slowest that you have patience for: ultrafast, superfast, veryfast, faster, fast, medium the defaultslow, slower, veryslow.How To Shift moov atom at the front of the file (Fast Start) - Youtube SEO
Useful if you are hosting the video, otherwise superfluous if uploading to a video service like YouTube. Scale to pixels in height, and automatically choose width that will preserve aspect, and then make sure the pixel format is compatible with dumb players. If your ffmpeg is outdated then you'll need to add -strict experimental to use -c:a aac. You can download a Linux build of ffmpeg or follow a step-by-step ffmpeg compilation guide to customize your build.
HandBrake is a tool for converting video from nearly any format to a selection of modern, widely supported codecs. When it opens, run the command s below:. Ubuntu Community Ask! Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Fastest way to convert videos batch or single?
Ask Question. Asked 6 years, 6 months ago. Active 3 years, 4 months ago. Viewed k times. Any ideas on how to best go about this process in Ubuntu? Basil Bourque 1 1 silver badge 8 8 bronze badges. Garrett Garrett 1 1 gold badge 3 3 silver badges 6 6 bronze badges. Active Oldest Votes. If you prefer command-line you can use ffmpeg or handbrake-cli. I am unaware of an open source encoder for version 9.
FFmpeg H. Try HandBrake. The Overflow Blog. Podcast Programming tutorials can be a real drag.
Featured on Meta.This document describes the supported formats muxers and demuxers provided by the libavformat library. The libavformat library provides some generic global options, which can be set on all the muxers and demuxers. In addition each muxer or demuxer may support so-called private options, which are specific for that component. Set probing size in bytes, i. A higher value will enable detecting more information in case it is dispersed into the stream, but will increase latency.
Must be an integer not lesser than It is by default. Only write platform- build- and time-independent data. This ensures that file and data checksums are reproducible and match between platforms. Its primary use is for regression testing.
Stop muxing at the end of the shortest stream. Specify how many microseconds are analyzed to probe the input. A higher value will enable detecting more accurate information, but will increase latency.
Set error detection flags. Set maximum buffering duration for interleaving. The duration is expressed in microseconds, and defaults to 10 seconds. To ensure all the streams are interleaved correctly, libavformat will wait until it has at least one packet for each stream before actually writing any packets to the output file.
When some streams are "sparse" i. This field specifies the maximum difference between the timestamps of the first and the last packet in the muxing queue, above which libavformat will output a packet regardless of whether it has queued a packet for all the streams.
If set to 0, libavformat will continue buffering packets until it has a packet for each stream, regardless of the maximum timestamp difference between the buffered packets. Shift timestamps to make them non-negative.
Also note that this affects only leading negative timestamps, and not non-monotonic negative timestamps. When shifting is enabled, all output timestamps are shifted by the same amount. Audio, video, and subtitles desynching and relative timestamp differences are preserved compared to how they would have been without shifting.
Default is -1 autowhich means that the underlying protocol will decide, 1 enables it, and has the effect of reducing the latency, 0 disables it and may increase IO throughput in some cases. Specifying a positive offset means that the corresponding streams are delayed bt the time duration specified in offset. Default value is 0 meaning that no offset is applied. Separator used to separate the fields printed on the command line about the Stream parameters. For example, to separate the fields with newlines and indentation:.
Specifies the maximum number of streams.We use Google Analytics, a web analytics service of Google Inc. The information regarding your use of this website that is generated by the cookie including your truncated IP address is transferred to a Google server in the United States and stored there.
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You can download the add-on here: www. With the decline of Flash and the explosive rise of mobile devicesmore and more content is being delivered as HTML5 video. However, video files themselves have a number of optimizations that you can make to improve their performance. One of the most important is that video files must be properly optimized for streaming online as HTML5 video.
Without this optimization videos can be delayed for hundreds of milliseconds and megabytes of bandwidth can be wasted by visitors just trying to play your videos. In this post I will show you how to optimize your video files for fast streaming. As discussed in our last postHTML5 video is a cross-browser way to watch video without needing a plug-in like Flash. As ofH. So when we talk about optimizing HTML5 video, what we are really talking about is how to optimize an MP4 video for faster playback.
And the way we do that has to do with the structure of the MP4 file, and how streaming video works. MP4 files consist of chunks of data called atoms. There are atoms to store things like subtitles or chapters, as well as obvious things like the video and audio data. Meta data about where the video and audio atoms are, as well as information about how to play the video like the dimensions and frames per second, is all stored in a special atom called the moov atom. You can think of the moov atom as a kind of table of contents for the MP4 file.
Searching to find the moov works fine if you already have the entire video file. You can start watching it without having to download the entire video first. When streaming, your browser requests the video and starts receiving the beginning of the file. It looks to see if the moov atom is near the start.
The Complete Guide for Using ffmpeg in Linux
If the moov atom is not near the start, it must either download the entire file to try and find the moovor the browser can download small different pieces of the video file, starting with data from the very end, in an attempt to find the moov atom.
All this seeking around trying to find the moov wastes time and bandwidth. Unfortunately, the video cannot play until the moov is located. We can see in the screen shot below a waterfall chart of a browser trying to stream an unoptimized MP4 file using HTML5 video:.Note that this filter is not FDA approved, nor are we medical professionals.
Nor has this filter been tested with anyone who has photosensitive epilepsy. FFmpeg and its photosensitivity filter are not making any medical claims.
That said, this is a new video filter that may help photosensitive people watch tv, play video games or even be used with a VR headset to block out epiletic triggers such as filtered sunlight when they are outside. Or you could use it against those annoying white flashes on your tv screen.
The filter fails on some input, such as the Incredibles 2 Screen Slaver scene.
It is not perfect. If you have other clips that you want this filter to work better on, please report them to us on our trac. See for yourself. We are not professionals. Please use this in your medical studies to advance epilepsy research. If you decide to use this in a medical setting, or make a hardware hdmi input output realtime tv filter, or find another use for this, please let me know.
This filter was a feature request of mine since FFmpeg 4. Some of the highlights:. We strongly recommend users, distributors, and system integrators to upgrade unless they use current git master. FFmpeg 3. This has been a long time coming but we wanted to give a proper closure to our participation in this run of the program and it takes time.
Sometimes it's just to get the final report for each project trimmed down, others, is finalizing whatever was still in progress when the program finished: final patches need to be merged, TODO lists stabilized, future plans agreed; you name it.
Without further ado, here's the silver-lining for each one of the projects we sought to complete during this Summer of Code season:. Stanislav Dolganov designed and implemented experimental support for motion estimation and compensation in the lossless FFV1 codec. The design and implementation is based on the snow video codec, which uses OBMC. Stanislav's work proved that significant compression gains can be achieved with inter frame compression. Petru Rares Sincraian added several self-tests to FFmpeg and successfully went through the in-some-cases tedious process of fine tuning tests parameters to avoid known and hard to avoid problems, like checksum mismatches due to rounding errors on the myriad of platforms we support.
His work has improved the code coverage of our self tests considerably. He also implemented a missing feature for the ALS decoder that enables floating-point sample decoding. We welcome him to keep maintaining his improvements and hope for great contributions to come. He succeeded in his task, and the FIFO muxer is now part of the main repository, alongside several other improvements he made in the process.
Jai Luthra's objective was to update the out-of-tree and pretty much abandoned MLP Meridian Lossless Packing encoder for libavcodec and improve it to enable encoding to the TrueHD format. For the qualification period the encoder was updated such that it was usable and throughout the summer, successfully improved adding support for multi-channel audio and TrueHD encoding. Jai's code has been merged into the main repository now.
While a few problems remain with respect to LFE channel and 32 bit sample handling, these are in the process of being fixed such that effort can be finally put in improving the encoder's speed and efficiency.
Davinder Singh investigated existing motion estimation and interpolation approaches from the available literature and previous work by our own: Michael Niedermayer, and implemented filters based on this research.
These filters allow motion interpolating frame rate conversion to be applied to a video, for example, to create a slow motion effect or change the frame rate while smoothly interpolating the video along the motion vectors. There's still work to be done to call these filters 'finished', which is rather hard all things considered, but we are looking optimistically at their future.
And that's it. We are happy with the results of the program and immensely thankful for the opportunity of working with such an amazing set of students. We can be a tough crowd but our mentors did an amazing job at hand holding our interns through their journey.