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  #1  
Old 10-28-2007, 06:07 PM
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Almoxil Almoxil is offline
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Post "End of song bug" test

“End of song bug” TEST

Hello, people. I finally managed to finish the test for the “end of song bug” on my Meizu M6 SP. Firmware version is 2004.1. It’s under tests, but except for APE support and a few other small improvements, it isn’t much different from the older 2003.2.

Here’s what I did:

Ripping:

I used Exact Audio Copy (v.095 beta 4) to rip two consecutive tracks without gaps between them. I obtained two WAV files (not compressed). The tracks in question are from Pink Floyd’s “Pulse”, which is a live concert – first two tracks from disc 2. EAC configurations are listed in the end of this post;

Encoding:

APE:

I downloaded and used Monkey’s Audio 3.99, which can be obtained here. Used Normal compression level (Extra-High doesn’t work);

FLAC:

I downloaded both FLAC codec and tools ver 1.2.1a here. Uset two compression levels (0 and 5). I used FLAC Frontend to convert the WAV files to FLAC;

MP3:

My LAME encoder (3.97) was already included with MediaCoder, but you can find it easily online (if you don’t have this version already installed with some other app). I used it to encode each of the two WAV files to MP3 (44,100 kHz, joint stereo, highest quality, automatic lowpass/highpass filters), using each of the following settings: CBR (160 kbits/s and 320 kbits/s); VBR (V 0 and V 3). The command lines for the encoding are listed in the end of this post;

Tagging and adding album art:

WAV files can’t hold tag information. For the encoded files (FLAC, APE and MP3) I used Mp3Tag, which can be found here to embed tags and album art. There are versions of the files without and with tags. For the tagged files, there are 2 versions: with and withoug album art.

Testing:

After, I loaded all the tracks (in a folder tree) to my Meizu M6 and started listening (using both the file browser and ID3 tag navigaton, when available). Below there is a summary of the results:


* after adding silence to MP3 files.

Adding silence frames to MP3 files:

I found a shareware app that allows adding silence frames at the beginning, end or in the middle of MP3 files, without decoding/re-encoding. It’s name is MP3 Frame Editor, and costs $15. Using the trial period (50 file saves), I used it to add 6 frames of silence (roughly 0.15 second) at the end of each MP3 file. The result is that some of the edited MP3 files didn’t show skipping. The others started to show harsh noises at the end. Adding more frames might alleviate de problem, but you'll end with a slightly longer gap between the tracks.

Conclusions:

My conclusions, after doing these tests, are that Meizu M6 SP has problems with MP3 files with no silence at the end. Constant bitrate files will have the issue more often. Other file formats (especially lossless) don’t seem to be affected by the issue. After adding silence frames at the end of affected MP3 files, some of them played correctly.

That makes me believe the problem should be a bug in the MP3 decoder or some problem involving that and buffering.

Configurations:

EAC options:

Extraction:

Fill up missing offset samples with silence – UNCHECKED;
No use of null samples for CRC calculations – CHECKED;
Synchronize between tracks – CHECKED;
Delete leading and trailing silence blocks – UNCHECKED;
Skip track extraction on read of sync erros – UNCHECKED;
Skip track extraction after duration longer than… times realtime – UNCHECKED;
After each… mins of extraction, cool down the drive for… – UNCHECKED;
Lock driver tray during extraction – CHECKED;
Extraction and compression priority – NORMAL;
Error recovery quality – HIGH;

Drive options / Extraction Method guide (drive for this test was a LG HL-DT-STCD-RW GCE-8526B):

Secure mode with following drive features (recommended) – SELECTED;
Drive has “Accurate Stream” feature – CHECKED;
Drive caches audio data – UNCHECKED;
Drive is capable of retrieving C2 error information – UNCHECKED;

Drive options / Gap Detection:

Gap/Index retrieval method – Detection Method B;
Detection accuracy – SECURE.

LAME settings for the test:

CBR 320 kbits/s:

lame -m j -q 0 -b 320 -p “<source file.wav>” “<dest file.mp3>”

CBR 160 kbits/s:

lame -m j -q 0 -b 160 -p “<source file.wav>” “<dest file.mp3>”

VBR V 0:

lame -m j -V 0 -q 0 --vbr-new –p “<source file.wav>” “<dest file.mp3>”

VBR V 3:

lame -m j -V 3 -q 0 --vbr-new –p “<source file.wav>” “<dest file.mp3>”
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  #2  
Old 10-30-2007, 07:11 AM
siwiwid siwiwid is offline
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did you also test it with WMA? how's the result with that?
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Old 10-30-2007, 08:40 AM
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No, I haven't tested WMA and OGG, but I'm planning on extending the tests to include these two formats.
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  #4  
Old 10-30-2007, 04:57 PM
oxid oxid is offline
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wma is useless, please try ogg
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Old 10-30-2007, 05:14 PM
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Why is WMA useless, oxid??
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  #6  
Old 11-20-2007, 09:34 AM
Changturkey Changturkey is offline
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Is this bug resolved in the 2.004.3/4 firmware?
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  #7  
Old 11-20-2007, 06:35 PM
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Guess not, Changturkey. I have this version installed on my M6 and it still skips.
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  #8  
Old 08-01-2008, 11:57 AM
DaremoS DaremoS is offline
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Default Sad news

This issue only applies to MP3 files... no other format is affected.
By ripping own MP3 there is no stuttering ("End of song bug"),
Converting to a new Mp3 the problem disappears.
But if there is an MP3 with the problem this won't disappear by changing the firmware because it's a problem of Philips audio decoder which isn't capable of compensate some encoding failures or extreme encoding.

Here is the answer from Meizu spokesman. Meizu fansite
In that thread there are some files to test the problem.
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