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Hi, there!
For synch problems, is it possible to adjust the video but not the audio on an MPEG2 file? By this I mean to speed up or to slow down the video while keeping the same audio speed from the original file before the modification. Of course, I understand that adjusting the video as opposed to the audio is more critical; hence, I think this is more plausible with part or parts of the file. Anyway, please be so kind to let me know if this is possible or how to do it.
Best to all,
CAL "Disco Mak"
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Do you want to adjust it to a valid mpeg2 framerate? DGpulldown can do that on progressive-encoded file, but it has to be valid. You can't adjust by any random hh:mm
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I think you have the whole process arse-about and are making life much harder for yourself.
Read my blog here.
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Hello, there!
Thanks for all replies.
The situation is this: there is a live videoclip with an original studio song. After adjusting for synch problems, everything fits perfectly except for 2 or 3 seconds. Obviously, I can isolate this section of 2 or 3 seconds and sych the audio there, but this would most likely mean speeding up or slowing down the audio, and I wouldn't like to do that so that I preserve the original audio. I would rather speed up or slow down the video to match the audio just within the limits of these 2 or 3 seconds or otherwise. By the way, by video I mean the video without audio.
CAL "Disco Mak"
P.S.: What is wrong with "match the video to the audio" as opposed to "match the audio to the video"? If it can be done one way, why cannot this be done the other way? -
Pinstripes23,
I am getting your point, but please let me ask you something:
Let's say that I have an MPEG videoclip at 29.97 frame rate which is a valid one. Then, I isolate a 2 seconds section at this 29.97 frame rate. After that, I speed up these 2 seconds section using your tool (thank you for letting me know of it!) at 30.00 frame rate which is also a valid one. My specific question is, can I join the MPEG section at 29.97 with the MPEG section at 30.00 and still be playable or recordable? Is this possible?
CAL "Disco Mak" -
Video requires massively more information than audio and we notice imperfections in it much more so than audio.Originally Posted by Disco Makberto
Because audio is normally sampled at 44,100 or 48,000 times per second, it can be stretched or squeezed easily without losing quality noticeably. Small changes in speed, a few percent, are imperceptible. (Use an audio editor, like audacity, or perhaps a command line toll like ac3scale.)
Whereas video is "sampled" at 24-30 times a second. To reinterpolate that you have to lose or create new frames, and that will probably be noticeably jerky, or fuzzy, and require reencoding, degrading the quality. -
Hi, AlanHK!
The other scenario (adjusting audio to the video) doesn't always work. You see, I received a videoclip that has some noticeable changes of audio speed in about 3 or 4 different sections. Needless to say, this was done to match the audio to the video, and the result was awful.
My proposed scenario (adjusting video to the audio) has been done succesfully. For instance, the clip "Return To Sender" by Elvis Presley from the movie "Girls, Girls, Girls" has an instance of it at YouTube with slowing down of the video in some sections. If I am allowed, I can try to find that clip and post the URL here.
So, again, how can my scenario be achieved? If I find a tool soon, I will post it here.
On a related note, to avoid further issues in respect to fuzziness, etc., I am willing to go mid-route, and that is, adusting the video just a little bit the first time around so that subsequently the audio be ajusted with minimal changes. In other words, a little bit of both.
CAL "Disco Mak"
P.S.: Yes, I was under the impression that an MPEG file with a custom frame rate needed to be re-encoded to a standard frame rate. Thanks for confirming my suspition! -
This changing of the speed of playback would be better served over a whole file than just a couple secs.Originally Posted by Disco Makberto
ex. If you had a 25fps (PAL) video but a 23.976fps audio, and you wanted to preserve the audio and the video. Under custom you would run the video at 23.976 -> 25. This would change the actual running time from 25 to 23.976fps, but insert flags to be played back at 25fps.
You could run your 29.97 mpeg through dgpulldown setting custom 30 -> 30. And it will play faster on your PC but you wouldn't be able to put it on dvd, since NTSC playback is 29.97. -
Hi, Pinstripes23!
Thanks for your helpful advice.
May I ask you something else? Let's say that I change the original MPEG video from 29.97 to 30.00 and save it as 30.00, and let's also assume that I am also satisfied with the new synchronization. Is it possible that I re-encode it back to 29.97 keeping the "new" synchronization? All information I have, including a previous post from AlanHK, tends to point in that direction.
In short, I still believe that this is possible to do. The only downside is the re-encoding requirement that will degrade the video, but since I am more of an audio fan than a video fan, that is not really very important to me (except in very extreme cases, of course).
Regards,
CAL "Makberto" -
Do you really think changing the playback speed over such a tiny amt in a span of 2 secs would make a difference?Originally Posted by Disco Makberto
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Hello again, Pinstripes23!
In answering your question, I would say so. However, the section might be a little bit more, like 3 or 4 seconds or slightly more. This scene is when a guy opens his mouth to sing some sentences, and the voice from the song starts before he opens his mouth, I believe. The rest of the videoclip is perfect after I tried to synchronize it.
Just for the record, there are two versions of this videoclip. One version has a slightly slower BPM audio while the other has a slightly faster BPM audio. The slightly faster BPM audio is more similar to the original song, so I am using the slightly faster BPM audio to join it with the video of the slightly lower BPM audio.
Take care,
CAL "Disco Mak" -
I think you are getting yourself all worked up over one video that was obvious done by someone with little or no idea about video.
With the exception of poorly encoded VBR, there is no sync problem that cannot be fixed by one the following
1. Adding or subtracting a delay factor
2. Changing the overall length
3. Editing the video to adjust segment by segment.
Shifts to audio are much easier to make, and easier to hide that changes to video. Cut even one frame from a video and the eyes will tell the brain that something is wrong. Cut audio properly and shift it around the 9 times out of 10 no-one will know.
I don't know why you like to make life so much more difficult than it has to be.Read my blog here.
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Hello, Gus1Inger!
Thank you very much for your reply.
Yes, I think you are right. My family always tells me why I always complicate things and never take the easy route or even, for some people, the "normal" route. Well, I don't even know the answer to that question myself. However, I can tell you that when I believe something is possible, easy or not, I never give up until I exhaust any and all roads. Please don't take me wrong, Gus1Inger, because I always appreciate your very valuable comments. As a matter of fact, you are like a professor to me with your vast knowledge.
Okay, returning to "adjusting video to audio", why do I have to drop or add frames? I think this only applies when I have 1 audio of 1 specific length and nothing more. However, remember that I can use the extended version, or 12" version, etc. and make the audio as long or as short as my specifications require. On the other hand, when I am limited to a specific audio of a specific length, I think you are absolutely right. Then, slowing down the video or parts of it would require extra audio that I don't have; conversely, speeding up the video or parts of it would let me with extra audio overhead.
Last but not least, please remember that these are just questions and nothing more. They might be eccentric questions but they are sincere, and I have no intention to cause any confusion. So I always appreciate your feedback and anybody else's.
CAL "Disco Mak" -
Re: Elvis Presley Video
Dear Readers,
As I was mentioning before, there is a clip by Elvis Presley using my proposed scenario. It is "Return To Sender" by Elvis Presley modified by Smithersjones. Please go to:
http://www.youtube.com/watch?v=i69qC-9vuFE
Please note the slowing down of the video at 00:44, 01:32, and 01:59 while keeping the original audio in its original state. This is what I am talking about, namely slowing down the video (or speeding up if the case may be) while keeping the original audio. I was asking this from a technical point of view and not from an artistic point of view; in other words, you could say that the end result is worse or better. However, whether you agree with this or not, nobody has said, "What you want to do is is definitely not possible". I think this video proves that it is indeed possible to do.
If you have any comments on additional ways or tools on how to achieve this scenario, please post to the group.
CAL "Disco Mak" -
If you notice it's not one continuos shot, there's a fade-out then goes back to its original state. That's a form of editing and not really what I thought you were describing.
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Pinstripes23,
I don't really understand what you are saying.
If I isolate a section of the clip, and then edit it independently, this will have a continuous shot. But then, when I join the edited section to the rest of the video, the modified part will just be the section I isolated it before.
Please pardon me for a couple of hours or more as I am going out to eat.
Take care,
CAL "Disco Mak" -
This is not what you started describing. this began as an alternate method of repairing audio sync issues. The clip you have provided makes no presence at all of maintaining audio sync during the slow motion sections. In fact, this has nothing to do with audio sync, but simple video editing and effects.
The clip you presented would be incredibly easy to do in Sony Vegas using the Velocity envelope. With this effect you can speed up and slow down the video, and still have it return to normal speed and maintain audio sync. Throw in a couple of simple dissolves, and you have your Elvis clip. If you look carefully, the clips go smoothly into the slow motion (simple to do in any editor), but at the end of each slow motion section, they dissolve back to the original speed video. They do not drift back to full speed in a continuous shot.
But again, this has nothing at all to do with audio sync, or repairing audio sync issues.Read my blog here.
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Well if you see this clip:Originally Posted by Disco Makberto
http://www.youtube.com/watch?v=P9dekS1mOqo&mode=related&search=
You can see continuous shots without any slow motion effects, or fade back to its original playback state. If you compare the 1:32 mark on both videos you will see what I mean. They are different sources obviously but for comparing purposes it's good enough since I haven't seen the original source of the edited clip you posted. So now what you want to do is speed up the slow motion so that playback is the same as the rest of the video? Is that what your goal is? -
Hello again, Pinstripes23!
I appreciate your response.
To begin with, we all agree that it is possible to slow down or speed up the video images independently of the audio sound so that we keep this audio sound in its original state without any speed up or slowing down of it, right? Let's not talk about whether the new video images are in synch or not with the original audio sound at this point. I just would like to be in agreement with you and all readers that it is possible to slow down or speed up the video images and not touching the original audio sound.
Now to my project.
There are two videoclips in perfect condition. Both have the same audio sound but with slightly different BPMs', and both have different video images. I prefer the faster audio sound, or in other words, the faster song. Please note that the difference between one audio sound from one videoclip and the other audio sound from the other videoclip is minimal. For most casual fans, it could unnoticeable; however, I still prefer the audio sound with the silgltly faster BPM.
In this next step, I took out the faster audio sound from its corresponding videoclip, and placed it to the other video images of the other videoclip. Of course, this resulted in some audio sych problems. Hence, I tried to fix it. I tried many ways, and the best way resulted in a section of 2 to 4 or 5 seconds when a singer is desynchronized. Other ways of synchronizing the video resulted in worse scenarios. In this desynchronized section, the singer from the audio sound starts singing before the singer from the video images opened his mouth.
Then, based on the Elvis Presley clip that changed the speed of some video images without changing the audio sound, I thought about changing the video images of the desynchronized section to match it to the original audio (in my case, this is the slightly faster song), and I came here for help.
What do I want to achieve in my final step? Obvioulsy, as I said in the beginning, it is possible to speed up the video and keep the original audio. Thus, I am completely sure that there is a point by which, by speeding up the desynchronized video images, the video images will catch up with the original audio sound and match perfectly. This also means that the original audio sound won't be touched because I would be adjusting the video image and not the audio sound. Conclusively, I am trying to know how to achieve this and try it.
Please let me make clear some points. I am not saying that this is the best method. I am not saying that this is not time consuming. I am not saying that there are no other easier ways to do this. And I am not saying that I will be completely satisfied with my end result. I am just saying that this is possible to do, it is an alternative method to sych problems, and I want to try it and see for myself.
If you have any other questions, please be so kind to post to the group.
Best to all,
CAL "Disco Mak" -
Hey, Guns1Inger!
I think that you have a valid point, but we are viewing things with a different prism. If you had said that the purpose of the slowing down of the video images on the videoclip by Elvis Presley is different to my purpose of slowing down the video images on my videoclip, I would have agreed with you 100%. In this light, the purpose of the speed modification of the video images on the Elvis Presley videoclip is to achieve an artistic result; on the other hand, the purpose of the speed modification of the video images on my videoclip is to achieve a synchronization result. The common ground on the Elvis Presley videoclip and my project is the fact that the speed mofication of the video images can be done without doing anything to the original audio.
The fact that the speed modification returns to normal after playback of it is fine with me. As a matter of fact, the video images speed modification I am trying to do is just for around 5 seconds, give or take a few. So, to achive this, I isolate the 5 seconds video images by cutting them from the whole videoclip, apply the speed mofication by guessing (if there is no better way) to just those 5 seconds video images, re-encode the 5 seconds video images to a standard FPS to keep the modification which ideally should be the same as the FPS of the non-modified video images, join the 5 seconds video images to the rest of the video images, and finally I apply the original audio which hasn't been modified at all to the whole video images. After that, I check the videoclip for synch issues. If the synch problem still persists which is very likely since I am doing everything by guessing, I do everything again, and apply a higher or slower speed modification to the isolated 5 seconds video images. I do this again and again until the 5 seconds video images are in sych to the audio sound.
Before anyting else, please, this is an "alternative way" of dealing with synchronization problems. My point is that this is possible. If anybody of you thinks that this is not possible, I would love to hear your comments and tell me why this is not possible. The merits of doing it this "alternative way" is something out of my scope. Some of you might think that this is the "stupid way" of doing it, but that doesn't help with the fact that you believe that it is not possible and why.
For more information, please read my response to Pinstripes23.
CAL "Dsico Mak" -
Are these clips on their own or did you cut them out of a bigger file? Are these clips from a movie? What are the running times of the audio? If they are the same song but one is faster, then how is it that everything else is in sync except for 2 secs when you do the replacing?
I realize you are trying to achieve something here but more info would definitely be needed. It could be that one clip is PAL the other is NTSC-film. PAL plays faster so it could be something as simple as speeding up the WHOLE NTSC-film clip and not just 2 secs. -
But you are not syncing the video and the audio, you are arbitrarily stretching the video to fill a space. Not the same thing at all. The video you have used as an example uses the slow motion for a deliberate effect. It has nothing to do with fitting video to audio. It is a visual pretension, and nothing else.
Knock yourself out doing it, by all means, but it still does not make any sense as a true solution.Read my blog here.
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Hello, Guns1Inger!
Okay, I got your point. I am not synchronizing the video images to the audio sound "on hands" with automatic review, but the intended end result will be a synchronized videoclip. So, whatever my approach is called, the intended end result is a synchronized videoclip which is the same intended end result if more standard approaches with video image to audio sound synchronization are taken.
While we are at it, this might not be as hard as it sounds, though obviously it is harder than all other approaches. There is a software entitled "Video Edit Magic Express v4.11" that allows me to create custom frame rates. So, I can take the 5 seconds video images, apply a custom frame rate, re-encode, add the original audio, and see how things go. Then, I can use a higher or slower custom frame rate for these 5 seconds video images until I achieve a better video image to audio sound synchronization.
Yes, I totally agree with you and your last point, and I have been saying this all along. My approach might not be a true solution, and I might be completely dissatisfied with my end result. However, it is possible to do, particularly by using "Video Edit Magic Express v4.11"....but first let me check if this software is not expensive.
Take care,
CAL "Disco Mak" -
Greetings, Pinstripes23!
Let me try to respond all your points.
>Are these clips on their own or did you cut them out of a bigger file?
No, they are on their own.
>Are these clips from a movie?
No, there are music video clips. Specifically, they are disco music video clips.
>What are the running times of the audio?
You mean the audio from the original CD or original LP?...If that is the case, it is about 7 something, I believe. But then again, you have the 7" version which is shorter and the 12" version which is longer.
>If they are the same song but one is faster, then how is it that everything else is in sync >except for 2 secs when you do the replacing?
Because the videoclip with the faster version is longer, I think 3:47, but the videoclip with the slower version is shorter, I think 3:42. What I did was to chop the longer version; in other words, I cut the fast version of 3:47 and made it 3:42.
On a side note, but not related to my project at all, I discovered that the fast version is in mono, so I will have to use the stereo CD version, speed it up to the BPM of the fast version, and chop it to 3:42
>I realize you are trying to achieve something here but more info would definitely be needed.
Thank you really very kindly.
>It could be that one clip is PAL the other is NTSC-film. PAL plays faster so it could be >something as simple as speeding up the WHOLE NTSC-film clip and not just 2 secs.
Wow! That is a great idea!!!! I hadn't thought specifically about that. Now that I think about it, I think that the faster videoclip is in PAL as it is from Europe while the slower videoclip is from the USA so this last one is in NTSC.
The only problem I see, well, not a problem but an inconvenience, is that the slower videoclip has some blank gaps in respect to the audio sound, so I would have to replace it with a continuous audio sound with the slower BPM.
Taking about audio sound BPM's, I remember that I used "BPM Checker" and tested both songs after extracting them from the videoclips. The faster song had a higher BPM while the slower song had a lower BPM.
While we are at it, is there a software that allows me to check the BPM of an audio sound that is part of a videoclip? In other words, can I check the BPM of the audio sound without extracting them from the videoclips first? This is to save steps, of course.
Well, I hope to hear from you soon.
Best regards,
CAL "Disco Mak" -
No I meant the from the audio clip, which you answer below.Originally Posted by Disco Makberto
Don't you mean the other way around? The faster version is 3:42 and the slower is 3:47.Originally Posted by Disco Makberto
But don't you get why I asked the question? If the songs are EXACTLY THE SAME, except one plays faster. In other words if you were to play the songs side by side, it will eventually get out of sync cuz one song is progressively faster than the other. Then how is it that you were able to replace the one song into the other video and have everything in sync except for 2 secs. If anything it should progressively get out of sync as the clip plays, and not just 2 secs worth. -
If the songs are exactly the same, then loading one into an audio editor and making it the same length as the other one should bring them back into sync. Sound Forge can do this easily without pitch shifting, as can goldwave and Audition. Audacity can change the length, but you then need to alter the pitch in a second pass. Not hard to do, you just have to remember to do it.
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Hi, one more time!
Please excuse me if I misguided you. When I said that both songs were the same, I didn't mean to say that they both have the same length. I was trying to say that one is not the studio version while the other one the remix version or the extended or edit version or even live version. Also, in music video clips, it is not unusual to add voiceovers or applauses, etc. in spite of using the original studio song. Thi is not the case with the music video clips I am discussing here as they have, music-wise, the same song that was used on the original vinyl or CD. So, again, both music video clips use the same song, except that one is longer and the other one is shorter. Also, the BPM's of these songs are different resulting from the difference in speed.
Please let me re-do the whole project from the beginning to give you exact data like BPM's, time, etc., and how I am doing everything.
In closing, please allow me a few days to give you exact data. I hope to have everything in 3 days or less.
CAL "Disco Mak" -
Pinstripes23,
No, I didn't just replace the slower song with the faster song, and that was it. There was desynchronization from beginning to end. Then, I remember I used Media Classic Player to find a synchronization factor. I tried and tried and the best scenario was one with a 2 to 3 or so seconds of desynchronization. I didn't go a step further and saved the "almost sychronized" video clip, but I will do it now. As a matter of fact, I will re-start the whole process to give you plenty of data.
Until soon,
CAL "Disco Mak" -
Pinstripes23, Guns1Inger, et. al.,
I ran into a problem as some of my tools are expired now. Hence, please allow me some weeks to re-start the project and give you full information since I need to save money to buy these softwares.
Pinstripes23, the faster song has a running time of 3:47 and the slower song has a running time of 3:44. Yes, I am sure of this as I double checked. This also means that the video images are longer and shorter on each video clip, respectively. While both songs are taken from the same source (CD or vinyl), and they are the same music-wise, the faster song ends at an instrumental bridge while the slower song ends at a chorus which means that the faster songs ends after the chorus.
Again, what I did was to chop the longest song to 3:44, and placed it to the video images of the slower song, resulting in a 2 or 3 seconds desynchronization after adjusting the whole video clip using MPC.
I will come back to this topic as soon as I can, and I will let you know exact information, and what I did.
Thanks again for all replies.
Carlos Albert L. "Disco Mak"
discomakberto at megamixers dot co dot uk
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