IPB

Welcome Guest ( Log In | Register )

FFMpeg/libav and SoX donít output identical WAVs when decoding FLAC/WV, Moved from General Audio (TOS #6)
2012
post Feb 7 2012, 22:58
Post #1





Group: Members
Posts: 71
Joined: 7-February 12
Member No.: 96993



Hello.

I noticed that the result of decoding (lossless) files to WAV is not bit-exact when using ffmpeg/avconv vs. sox.

The difference is very small but It doesn't take place only at the header of the file. xdelta tells me it takes place every 8388608 bytes.

Also, the filesize is different (e.g. 51525310 with avconv and 51525308 with sox).

The result is exactly the same if the source is FLAC or WavPack. So, this is not codec-specific.

Is there an explanation to this? Is one of the tools at fault or the difference is not in audio data?
Go to the top of the page
+Quote Post
 
Start new topic
Replies
db1989
post Feb 7 2012, 23:11
Post #2





Group: Super Moderator
Posts: 5275
Joined: 23-June 06
Member No.: 32180



QUOTE (2012 @ Feb 7 2012, 21:58) *
The difference is very small but It doesn't take place only at the header of the file. xdelta tells me it takes place every 8388608 bytes.

What is the difference?

Are you comparing the actual audio streams or just the entire files (i.e. including frame headers, etc.)?

If the former, do you mean that the decoders produce different streams to one another? What about when they are compared to the original input file? Does either produce an identical stream to that?

QUOTE
Also, the filesize is different (e.g. 51525310 with avconv and 51525308 with sox).

Again: does either produce an identical file-size to the input WAV?

Sorry, but a lot more information is needed here.
Go to the top of the page
+Quote Post

Posts in this topic


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 1st October 2014 - 00:37