Re: [gentoo-user] Re: Movie editing softeware
On Wed, 22 Dec 2021 20:39:59 +, Wols Lists wrote: > Now emerging! I shall have to play with it, but it looks just what the > doctor ordered. I *believe* a ts contains an mpeg2 ... let's hope! AFAIR recall a .ts (Transport Stream) file is intended for broadcast and so contains more redundant information to allow for unreliable transmission - MythTV records .ts files. Converting for MPEG without reencoding gives the same video but in a smaller file. -- Neil Bothwick What do you get if you cross an agnostic, an insomniac and adyslexic? Someone who lies awake at night wondering if there really is a dog. pgplETHPHWu4k.pgp Description: OpenPGP digital signature
Re: [gentoo-user] Movie editing softeware
On Wed, 22 Dec 2021 10:37:32 +, Michael wrote: > > Note that some editing software can only cut at the iframes, and it's > > also fairly common to only be able to cut at the iframes unless it's > > re-encoding the data. That can be a major source of frustration. > > > LMP > > Yes, I've noticed this with kdenlive and from what I recall from years > ago, avidemux too. I can't recall if there was some GUI option to > change this - I never found it. Avidemux can cut anywhere, but then you have to reencode the portions around the cuts, but not the whole thing.Avidemux is a bit limited and old fashioned looking, but the one thing it is particularly good at is quickly removing portions of videos. For anything more adventurous, I'd probably use Openshot. -- Neil Bothwick Eye of newt, toe of frog, regular Coke and fries to go, please. pgpZKhoIf2pS5.pgp Description: OpenPGP digital signature
RE: [gentoo-user] Re: Movie editing softeware
> >-Original Message- >From: Grant Edwards >Sent: Wednesday, December 22, 2021 8:18 AM >To: gentoo-user@lists.gentoo.org >Subject: [gentoo-user] Re: Movie editing softeware > >On 2021-12-21, Laurence Perkins wrote: > >> Note that some editing software can only cut at the iframes, and it's >> also fairly common to only be able to cut at the iframes unless it's >> re-encoding the data. > >AFAIUI, it's not even theoretically possible to cut anyplace other than the >I-frames without decoding and reencoding at least the portion of the stream >where the cut is being made. While it might be possible to copy the rest of >the stream, I don't know of any editors that will do that. > >-- >Grant > > Oh, you can do it, it'll just mess up every frame between where you cut it and the next iframe so sensible software that doesn't want to reencode it refuses to do so. But the playback decoders won't generally choke on it or anything. It's basically the same as a full+incremental backup scheme, only with video frames. Chop some diffs out of the middle and the stuff between there and the next full goes... strange. But what I meant was that cutting to the whole GOP is ALL that some software can do and it won't even try to reencode. LMP
Re: [gentoo-user] Apparently 2.4 is not >= 2.2?
On Tue, 21 Dec 2021 20:21:17 -0500 Jack wrote: > I may well be wront, but it looks like the problems are not due to > version, but to python-target mismatches. You may need to rebuild > some stuff first, such as pytest-runner and mako. You are probably right: I've spent more time playing with PYTHON*TARGET variables and succesive rebuilds on this machine than actually doing any work for about a year. Annoyance is that I don't do anything else with Python here so it's only for the package manager. This is for a fresh build from a recent stage3. It shouldn't be this painful to just start a new system. -- Steven Lembark Workhorse Computing lemb...@wrkhors.com +1 888 359 3508
Re: [gentoo-user] Re: Apparently 2.4 is not >= 2.2?
Sorry for the delay. > Post the output of: > > emerge --info dev-lang/python-exec https://pastebin.com/5kQPpRsb -- Steven Lembark Workhorse Computing lemb...@wrkhors.com +1 888 359 3508
Re: [gentoo-user] Re: Movie editing softeware
On 22/12/2021 19:27, Daniel Pielmeier wrote: TTCut can do "smart cutting" by encoding only the affected GOP [2]. However it only works for Mpeg2 Video and Mpeg2 Audio or Dolby AC-3 Audio. I have not tested it but VidCutter [3] should also be capable of doing so and as I see there is no restriction on the codecs. They are the only ones I am aware of supporting this feature and they are packaged for Gentoo. Now emerging! I shall have to play with it, but it looks just what the doctor ordered. I *believe* a ts contains an mpeg2 ... let's hope! Cheers, Wol
Re: [gentoo-user] Re: Movie editing softeware
Wol schrieb am 22.12.21 um 19:45: What is an i-frame? As I understood it, typically when you had a scene change, a frame was written in full, then subsequent frames were stored as diffs. Is that what an i-frame is? Wikipedia [1] to the help. In which case, surely it can't be that tricky to delete a block without having to decode/encode more than a few frames? Encoding only the affected region is tricky because you need to use the same codec parameters (encoding profile, resolution, colour space, FPS, bit depth, bitrate, and possibly more parameters which are also codec dependent) like the rest of the unaffected portion of the video to be able to concatenate it again afterwards with the rest of the video. Also it is tricky to keep video an audio in sync when having a lot of cut points. Probably there are other issues depending on the required codecs. So making it work for every codec even only for the popular ones might be a lot of work. TTCut can do "smart cutting" by encoding only the affected GOP [2]. However it only works for Mpeg2 Video and Mpeg2 Audio or Dolby AC-3 Audio. I have not tested it but VidCutter [3] should also be capable of doing so and as I see there is no restriction on the codecs. They are the only ones I am aware of supporting this feature and they are packaged for Gentoo. [1] https://en.wikipedia.org/wiki/Video_compression_picture_types [2] https://en.wikipedia.org/wiki/Group_of_pictures [3] https://github.com/ozmartian/vidcutter -- Regards Daniel
Re: [gentoo-user] Re: Movie editing softeware
On 22/12/2021 16:17, Grant Edwards wrote: On 2021-12-21, Laurence Perkins wrote: Note that some editing software can only cut at the iframes, and it's also fairly common to only be able to cut at the iframes unless it's re-encoding the data. AFAIUI, it's not even theoretically possible to cut anyplace other than the I-frames without decoding and reencoding at least the portion of the stream where the cut is being made. While it might be possible to copy the rest of the stream, I don't know of any editors that will do that. What is an i-frame? As I understood it, typically when you had a scene change, a frame was written in full, then subsequent frames were stored as diffs. Is that what an i-frame is? In which case, surely it can't be that tricky to delete a block without having to decode/encode more than a few frames? And how come PVRs do it so easily? Cheers, Wol
[gentoo-user] Re: Movie editing softeware
On 2021-12-21, Wols Lists wrote: > Oh - and as for using the command line, it's all very well until you > try and figure out where to tell the command line to cut the video > file - I really don't want to have to run the command line hundreds > of times, checking the output every time, and throwing away the ones > that cut in the wrong place. You don't need to figure out the edit points by trail-and-error using the command line. There are plenty of bullet-proof video players that will allow you to easily identify the exact point in a stream. > Oh, and if I use some video editing software to find the exact > millisecond I want to cut, it STILL cuts it in completely the wrong > place ... If you're trying to do cuts with a muxer (without re-encoding), you can only cut at certain pre-defined points in the stream, and the software will have to pick one of the points either side of the position you specified. If you want to cut at exact frames, you'll have to re-encode.
[gentoo-user] Re: Movie editing softeware
On 2021-12-21, Laurence Perkins wrote: > Note that some editing software can only cut at the iframes, and > it's also fairly common to only be able to cut at the iframes unless > it's re-encoding the data. AFAIUI, it's not even theoretically possible to cut anyplace other than the I-frames without decoding and reencoding at least the portion of the stream where the cut is being made. While it might be possible to copy the rest of the stream, I don't know of any editors that will do that. -- Grant
Re: [gentoo-user] Movie editing softeware
On Tuesday, 21 December 2021 22:32:14 GMT Laurence Perkins wrote: > >> > >>From: Wols Lists > >>Oh - and as for using the command line, it's all very well until you try > >>and figure out where to tell the command line to cut the video file - I > >>really don't want to have to run the command line hundreds of times, > >>checking the output every time, and throwing away the ones that cut in > >>the wrong place. Oh, and if I use some video editing software to find the > >>exact millisecond I want to cut, it STILL cuts it in completely the wrong > >>place ... > >>Cheers, > >>Wol > >> > >> > > > Note that some editing software can only cut at the iframes, and it's also > fairly common to only be able to cut at the iframes unless it's re-encoding > the data. That can be a major source of frustration. > LMP Yes, I've noticed this with kdenlive and from what I recall from years ago, avidemux too. I can't recall if there was some GUI option to change this - I never found it. I use mpv to identify the exact timestamp where I want to make a cut and then tell ffmpeg to do so. Whether I transcode any/all streams, or remux to a different container at the same time, ffmpeg just works, but the process takes more than point 'n click. I'll give openshot a ... shot one day to see if it is more user friendly. signature.asc Description: This is a digitally signed message part.
