Hot answers tagged file-formats
25
FLAC is fully lossless and can reproduce a sample-accurate waveform. It's awesome.
The main reason not to encode everything as FLAC is simple convenience. For many applications (using them in most DAWs, for example) you'll have to transcode them back to .WAV which takes some time. Not much, but some. Whether this matters or not is entirely up to your ...
21
Mp3 is "MPEG-1 or MPEG-2 Audio Layer 3 (or III)" and MP4 is "MPEG-4 Part 14". Mp3 is an audio compression and file type, mp4 is a file container capable of holding any video compression (e.g. h.264). So MP4 isn't an extension on MP3 like a bucket isn't an improvement on sand. Read the wikipedia articles for more information.
MP4
MP3
17
You won't lose any data. In fact, FLAC has much better meta-data support so you actually gain data if, after converting, you tag the FLAC files with meta-data like author, BPM, song title, etc.
The only reason I can think of not to save things as FLAC is compatibility. Not all software will understand a FLAC file (example: iTunes, Logic) but I've never met ...
16
If you're happy using the Terminal, then you could try the following command loop:
for f in *.flac; do ffmpeg -i "$f" -vf "crop=((in_w/2)*2):((in_h/2)*2)" -c:a alac "${f%.flac}.m4a"; done
This will simply cycle through all the .flac files sitting in the current directory and convert them all to .alac until they're all done. I can confirm that this works ...
13
MPEG-1 Layer 3 is complex stuff. I recommend starting your reading here: http://oreilly.com/catalog/mp3/chapter/ch02.html
Another resource that I found helpful to get started with is at: http://www.mp3-tech.org/
In a nutshell, MP3 encoding works by taking a frame (say, 576 samples, which is the smallest frame size for standard MP3) and making a spectral ...
8
What you're thinking of is AAC, not MP4. MP4 is often used as the container for AAC-compressed audio.
AAC uses many of the same principles as MP3, essentially throwing away frequencies that the listener probably won't miss. The main difference between the two is which frequencies each chooses to throw away. AAC was basically "let's take what we learned from ...
8
Audio quality/loss
FLAC is, by definition, loss-less. From a FLAC file you can recreate the original PCM stream, bit-for-bit.
Vorbis (sometimes referred to as just Ogg when you know the codec is for audio-only), the scheme used in the Ogg container to do the compression, is a lossy compressor, same as MP3. From an Ogg Vorbis encoded file you cannot ...
8
I don't understand why ths wasn't mentioned earlier, but even without looking whether or not software supports the FLAC format, there is a general reason why you don't want to use it.
Flac saves you about 60% of the space and gives you spiffing tag info, but at a price I am not going to pay at any moment in my recording-workflow: it costs CPU power to ...
8
Although you've already mentioned it, ffmpeg is the canonical (Linux) tool for this. I would recommend invoking ffmpeg directly (from the command line) with something like:
ffmpeg -i [infile].flv -vn -acodec libmp3lame -ab 128k [outfile].mp3
... where
-vn disable video
-acodec libmp3lame convert audio to mp3 using the lame codec
-ab 128k ...
7
X Lossless Decoder (XLD) is a great prefect lossless ripping and batch conversion tool for the Mac.
I've heard great things about getting perfect lossless rips using Exact Audio Copy (EAC) on Windows, though I'm not sure if it supports conversion.
7
I don't understand what you mean by "changing a single sample". As you may know, samples are 16 or 24 bit long strings that describe the particular sample, but the file format won't comply to this as easy.
AIFF and WAV are both lossless formats, in Pulse Code Modulation (also referred as Linear Pulse Code Modulation or LPCM due to the quantization ...
6
When you import a lossy audio file into editing software, that file is decoded into an audio waveform. This is a "lossless" waveform in that it's not stored in a compressed format, but it's not the same as the original waveform that your lossy file was approximating.
So there are already three concepts involved:
The original waveform, which is to say, ...
5
I think this image from Wikipedia says it best:
AVCHD is not a codec, but it is also not just a container.
Just like "every other" container, AVCHD features:
Video streams
Audio streams
Subtitles
But in addition, for example:
Playlists
Menu presentation (like in a DVD)
Is it simply a specification that specifies a particular combination of ...
4
Since FLAC is the "free lossless audio codec" it should retain the same bit-for-bit audio data. This also implies that the audio parameters (bit rate, sample rate, channel count will be the same. What's not certain is if other meta-data in the .wav file (e.g. comments, cues, etc) will be preserved when converted to flac and back again. If you have none of ...
4
File formats are essentially wrappers, a container of sorts. The video information is encoded in a codec (Coder/Decoder). Some file formats only work with certain codecs. This is due (in part) to corporate/organizational pissing contests (or format wars - remember dvd+ vs. dvd -?). Codecs come with varying degrees of compression. The more compressed a codec ...
4
It's just how bit rate is defined. It's "bits of data per second". So if you compress something, even losslessly, it's at a lower bitrate.
The association between "low bitrate" and "low quality" comes from lossy codecs like MP3, which let you trade off quality for file size. Lossless codecs like FLAC instead let you trade off CPU time (at least during ...
4
Personally I always choose MP4 container and the H.264 codec as this is also the codec YouTube uses in the final video stream.
What key-frame rates and compression you need really depends on the footage and it's unfortunately close to impossible to give as a generic answer for this reason.
If you have a lot of movements you will need key-frames more often ...
4
It's the compression!
The color resolution is a factor, but not such a big one. In this case the compression is the biggest factor. If you assume that both the 4K Edition and the 4K Cineform contain the same material, 4K Cineform contains more than 13x the information (as stated on the timescapes.org products page).
But is more really better? Cineform ...
3
The video may already contain audio in MP3 format. In this case it's better to copy the stream. This avoids re-encoding the audio, which takes time and involves quality loss.
ffmpeg -i [infile].flv -vn -acodec copy [outfile].mp3
... where
-vn drop the video stream
-acodec copy copy audio stream directly to output mp3 file
3
if you want convert everything flac file in folders and subfolders recursively add the /r to the for loop command like so:
for /r %%a in (".flac") do ffmpeg -i "%%a" -acodec alac "%%a.m4a" -map_metadata input.flac:output.m4a
The only problem i have with this is that filenames come out like
output.flac.m4a
I have no idea how to fix that at the end, but ...
3
You may find a lot of subjective answers here, and some of the quality seems to be dependent on what you play the files on - for example AAC and low quality mp3s will be fine on your iPod through headphones, but pop them on a decent system with good speakers and they will sound crap (Skeptics question here)
Each of the lossy formats has its own way of ...
3
Your comparison of WMV to MP4 is a little bit confusing, because you're comparing apples and oranges.
MP4 is a container format, which may contain a variety of audio and video formats. Most commonly, an MP4 file will contain wither an MPEG-4 Part 10 (aka H.264) or MPEG-4 Part 2 video stream, although it can contain MPEG-2 or MPEG-1 video streams. There ...
3
Practically any time you convert from one lossy format to another, you will lose quality. How much quality, and what precise effect it will have depends on your encoder, and its algorithm.
It also depends on what you mean by quality. Are you referring to bitrate? Or the encoder settings used to generate the file?
It may be possible to transcode from one ...
3
Well, the short answer is, you can't.
The longer answer: DVD uses MPEG2 compression, which is a lot less efficient than MPEG4 (aka h.264). In other words it can't get the same quality from the same file size as MPEG4 does.
So you can choose: similar file size, or similar quality, but not both.
3
Since FLAC by definition is lossless compression there shouldn't be any data loss unless there is an error during encoding.
In my experience, when you compress a WAV file to FLAC it reduces the size by about 1/3. (The FLAC web site claims even better compression, and as @Mulvya pointed out in the comments, this is due to the content of the recording). The ...
3
Using Quicktime Player 7 you can export any movie file as an Image Sequence
Open your .mov file using Quicktime 7
File > Export
In the Export dropdown select Movie to Image Sequence
Open the options and set the export format (eg JPEG or PNG)
If you want just the current frame leave the frames per second blank. Otherwise, enter hte videos frame rate and ...
3
Premiere Pro CS5 should be able to import H.264 video, IIRC, however it may be having trouble with the audio and/or container format. With ffmpeg try re-muxing the video stream without the audio:
ffmpeg -i input -an -codec:v copy output.mp4 -an -codec:v copy output.avi
If both output.mp4 and output.avi work then we know that the issue lies with the audio ...
3
The simple answer is yes for a couple of reasons:
if the number of pixels is the same*, the colour depth can have a huge impact on the size. 12 bit = 4096 in decimal. So if the difference between the two formats is 13.2 (330/25) that could be easily explained as the difference between 8 bit and 12 bit is could be a 16x difference.
the content on each of ...
3
"I copy pasted Final Cut Events and Final Cut Projects folders to my external HD but I don't know how to restore it into project in FC. Any help is appreciated."
It's better to perform this type of operation from within FCPX, instead of the Finder via copy/paste. With the project selected in the Project Library, choose File->Move Project... As long as you ...
3
MP4 with AAC audio and h.264 video is definitely playable on the PS3, and since it's an extension of Apple's .mov files, it should work on all the iDevices too.
For maximum compatibility, use the h.264 'baseline' profile, and avoid AAC-HE.
Older devices (like some DVD players) may require XVID video and AC3 audio in an AVI container, but that won't apply ...
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