I understood this page to mean that queuing in pyglet provides a gapless transition between audio tracks. But when I test it out, there is a noticeable gap. Has anyone here worked with gapless audio in pyglet?
Example:
player = pyglet.media.Player()
source1 = pyglet.media.load([file1]) # adding streaming=False doesn't fix the issue
source2 = pyglet.media.load([file2])
player.queue(source1)
player.queue(source2)
player.play()
player.seek([time]) # to avoid having to wait until the end of the track. removing this doesn't fix the gap issue
pyglet.app.run()
I would suggest you either edit your url1 and url2 into caching them locally if they're external sources. And then use Player().time to identify when you're about to reach the end. And then call player.next_source.
Or if it's local files and you don't want to programatically solve the problem you could chop up the audio files in something like Audacity to make them seamless on start/stop.
You could also experiment with having multiple players and layer them on top of each other. But if you're only interested in audio playback, there's other alternatives.
It turns out that there were 2 problems.
The first one: I should have used
source_group = pyglet.media.SourceGroup()
source_group.add(source1)
source_group.add(source2)
player.queue(source_group)
The second one: mp3 files are apparently slightly padded at the beginning and at the end, so that is where the gap is coming from. However, this does not seem to be an issue with any other file type.
Related
I've been looking around Swift documentation to save an audio output from AVAudioEngine but I couldn't find any useful tip.
Any suggestion?
Solution
I found a way around thanks to matt's answer.
Here a sample code of how to save an audio after passing it through an AVAudioEngine (i think that technically it's before)
newAudio = AVAudioFile(forWriting: newAudio.url, settings: nil, error: NSErrorPointer())
//Your new file on which you want to save some changed audio, and prepared to be bufferd in some new data...
var audioPlayerNode = AVAudioPlayerNode() //or your Time pitch unit if pitch changed
//Now install a Tap on the output bus to "record" the transformed file on a our newAudio file.
audioPlayerNode.installTapOnBus(0, bufferSize: (AVAudioFrameCount(audioPlayer.duration)), format: opffb){
(buffer: AVAudioPCMBuffer!, time: AVAudioTime!) in
if (self.newAudio.length) < (self.audioFile.length){//Let us know when to stop saving the file, otherwise saving infinitely
self.newAudio.writeFromBuffer(buffer, error: NSErrorPointer())//let's write the buffer result into our file
}else{
audioPlayerNode.removeTapOnBus(0)//if we dont remove it, will keep on tapping infinitely
println("Did you like it? Please, vote up for my question")
}
}
Hope this helps !
One issue to solve:
Sometimes, your outputNode is shorter than the input: if you accelerate the time rate by 2, your audio will be 2 times shorter. This is the issue im facing for now since my condition for saving the file is (line 10)
if(newAudio.length) < (self.audioFile.length)//audiofile being the original(long) audio and newAudio being the new changed (shorter) audio.
Any help here?
Yes, it's quite easy. You simply put a tap on a node and save the buffer into a file.
Unfortunately this means you have to play through the node. I was hoping that AVAudioEngine would let me process one sound file into another directly, but apparently that's impossible - you have to play and process in real time.
Offline rendering Worked for me using GenericOutput AudioUnit. Please check this link, I have done mixing two,three audios offline and combine it to a single file. Not the same scenario but it may help you for getting some idea. core audio offline rendering GenericOutput
We are developing a game about driving awareness.
The problem is we need to show videos to the user if he makes any mistakes after completing driving. For example, if he makes two mistakes we need to show two videos at the end of the game.
Can you help with this. I don't have any idea.
#solus already gave you an answer, regarding "how to play a (pre-registered) video from your application". However, from what I've understood, you are asking about saving (and visualize) a kind of replay for the "wrong" actions, performed by the player. This is not an easy task, and I don't think that you can receive an exaustive answer, but only some advices. I will try to give you my own ones.
First of all, you should "capture" the position of the player's car, in various time periods.
As an example, you could read player's car position every 0.2 seconds, and save it into a structure (example: a List).
Then, you would implement some logic to detect the "wrong" actions (crashes, speeding...They obviously depend on your game) and save a reference to the pair ["mistake", "relevant portion of the list containg car's positions for that event"].
Now, you have all what you need to recreate a replay of the action: that is, making the car "driving alone", by reading the previously saved positions (that will act as waypoints for generating the route).
Obviously, you also have to deal with the camera's position and rotation: just leave it attached to the car (as the normal "in-game" action), or modify it during time to catch the more interesting angulations, as the AAA racing games do (this will make the overall task more difficult, of course).
Unity will import a video as a MovieTexture. It will be converted to the native Theora/Vorbis (Ogg) format. (Use ffmpeg2theora if import fails.)
Simply apply it as you would any texture. You could use a plane or a flat cube. You should adjust its localScale to the aspect ratio of your video (movie.width/(float)movie.height).
Put the attached audioclip in an AudioSource. Then call movie.Play() and audio.Play().
You could also load the video from a local file path or the web (in the correct format).
var movie = new WWW(#"file://C:\videos\myvideo.ogv").movie;
...
if(movie.isReadyToPlay)
{
renderer.material.mainTexture = movie;
audio.clip = movie.audioClip;
movie.Play();
audio.clip.Play();
}
Use MovieTexture, but do not forget to install QuickTime, you need it to import movie clip (.mov file for example).
I have a GPUImageColorDodgeBlend filter with two inputs connected:
A GPUImageVideoCamera which is getting frames from the iPhone video camera.
A GPUImageMovie which is an (MP4) video file that I want to have laid over the live camera feed.
The GPUImageColorDodgeBlend is then connected to two outputs:
A GPUImageImageView to provide a live preview of the blend in action.
A GPUImageMovieWriter to write the movie to storage once a record button is pressed.
Now, before the video starts recording, everything works OK 100% of the time. The GPUImageVideo is blended over the live camera video fine, and no issues or warnings are reported.
However, when the GPUImageMovieWriter starts recording, things start to go wrong randomly. About 80-90% of the time, the GPUImageMovieWriter works perfectly, there are no errors or warnings and the output video is written correctly.
However, about 10-20% of the time (and from what I can see, this is fairly random), things seem to go wrong during the recording process (although the on-screen preview continues to work fine).
Specifically, I start getting hundreds & hundreds of Program appending pixel buffer at time: errors.
This error originates from the - (void)newFrameReadyAtTime:(CMTime)frameTime atIndex:(NSInteger)textureIndex method in GPUImageWriter.
This issue is triggered by problems with the frameTime values that are reported to this method.
From what I can see, the problem is caused by the writer sometimes receiving frames numbered by the video camera (which tend to have extremely high time values like 64616612394291 with a timescale of 1000000000). But, then sometimes the writer gets frames numbered by the GPUImageMovie which are numbered much lower (like 200200 with a timescale of 30000).
It seems that GPUImageWriter is happy as long as the frame values are increasing, but once the frame value decreases, it stops writing and just emits Program appending pixel buffer at time: errors.
I seem to be doing something fairly common, and this hasn't been reported anywhere as a bug, so my questions are (answers to any or all of these are appreciated -- they don't all need to necessarily be answered sequentially as separate questions):
Where do the frameTime values come from -- why does it seem so arbitrary whether the frameTime is numbered according to the GPUImageVideoCamera source or the GPUImageMovie source? Why does it alternative between each -- shouldn't the frame numbering scheme be uniform across all frames?
Am I correct in thinking that this issue is caused by non-increasing frameTimes?
...if so, why does GPUImageView accept and display the frameTimes just fine on the screen 100% of the time, yet GPUImageMovieWriter requires them to be ordered?
...and if so, how can I ensure that the frameTimes that come in are valid? I tried adding if (frameTime.value < previousFrameTime.value) return; to skip any lesser-numbered frames which works -- most of the time. Unfortunately, when I set playsAtActualSpeed on the GPUImageMovie this tends to become far less effective as all the frames end up getting skipped after a certain point.
...or perhaps this is a bug, in which case I'll need to report it on GitHub -- but I'd be interested to know if there's something I've overlooked here in how the frameTimes work.
I've found a potential solution to this issue, which I've implemented as a hack for now, but could conceivably be extended to a proper solution.
I've traced the source of the timing back to GPUImageTwoInputFilter which essentially multiplexes the two input sources into a single output of frames.
In the method - (void)newFrameReadyAtTime:(CMTime)frameTime atIndex:(NSInteger)textureIndex, the filter waits until it has collected a frame from the first source (textureInput == 0) and the second, and then forwards on these frames to its targets.
The problem (the way I see it) is that the method simply uses the frameTime of whichever frame comes in second (excluding the cases of still images for which CMTIME_IS_INDEFINTE(frameTime) == YES which I'm not considering for now because I don't work with still images) which may not always be the same frame (for whatever reason).
The relevant code which checks for both frames and sends them on for processing is as follows:
if ((hasReceivedFirstFrame && hasReceivedSecondFrame) || updatedMovieFrameOppositeStillImage)
{
[super newFrameReadyAtTime:frameTime atIndex:0]; // this line has the problem
hasReceivedFirstFrame = NO;
hasReceivedSecondFrame = NO;
}
What I've done is adjusted the above code to [super newFrameReadyAtTime:firstFrameTime atIndex:0] so that it always uses the frameTime from the first input and totally ignores the frameTime from the second input. So far, it's all working fine like this. (Would still be interested for someone to let me know why this is written this way, given that GPUImageMovieWriter seems to insist on increasing frameTimes, which the method as-is doesn't guarantee.)
Caveat: This will almost certainly break entirely if you work only with still images, in which case you will have CMTIME_IS_INDEFINITE(frameTime) == YES for your first input'sframeTime.
I'm trying to use GDCL MP4 Muxer with my RTSP Source Filter. They work fine together except after stopping the graph, muxer doesn't finilize the file and write the reqiured tables to the end of file via file writer (some parts are written starting from moov but not the time table values). When I try another RTSP source filter (which I don't have its source codes), table values are created with GDCL MP4 Muxer.
But when I try Elecard's MP4 Muxer, it works fine with my RTSP Source Filter. So, there is an incompatibility. I examined GDCL's source codes but couldn't find what it was expecting from me. I already calculate and set timestamp values to samples using SetTime method. But GDCL still doesn't finilaze file. Is it caused by missing information or missing signal when graph stops? What can be the problem, any ideas?
One thing you should be aware of regarding Geraint's MP4 Mux is that it is checking incoming media samples to have both start and stop time. You might be having only .tStart/AM_SAMPLE_TIMEVALID which still makes sense for video, but this would be a problem.
So the samples have to have stop time, or you need to fix this in multiplexer code.
A typical symptom for the problem is that generated files are empty or of zero duration.
We are seeing this when "tying" two video files together.
Example we have Ad video that is segmented and content file which is also segmented.
We create a new file which has both Ad and content segment information together. However we are seeing an issue where either the Ad content is truncated or the content starts having A/V sync issues.
Both ad and content are segmented the same way , 5 sec segmentation. however since Ads are variable length the result file may have left over segment something like:
#EXTM3U
#EXT-X-TARGETDURATION:5
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:5,
fileSequence6.ts
#EXTINF:5,
fileSequence7.ts
#EXTINF:4,
fileSequence8.ts
#EXTINF:5,
fileSequence0.ts
#EXTINF:5,
fileSequence1.ts
#EXTINF:5,
fileSequence2.ts
#EXTINF:3,
fileSequence3.ts
Is this the proper way to play 2 files one after the other without rebuffering?
should generate-variant-plist be used to a play list of 2 files?
When you have a break in the stream to switch to a commercial, ad, or alternate video source then you want to introduce the discontinuity tag before the start of the next segment, for example:
#EXTM3U
#EXT-X-TARGETDURATION:5
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:5,
movie0.ts
#EXTINF:2,
movie1.ts
#EXT-X-DISCONTINUITY
#EXTINF:5,
commercial0.ts
#EXTINF:5,
commercial1.ts
#EXTINF:3,
commercial2.ts
This gets a little more complicated if you encrypt the streams because they use progressive encryption based on the prior segments encryption state and the sequence number which come together to form an "Initialization Vector". If you break the stream you have to reset the initialization vector so that the encryption/decryption can continue uninterrupted. This is an involved process so best to just search on Initialization Vector in Apple's docs.