topic Re: software MP3 decoder for Kinetis MK64 in Kinetis Microcontrollers

software MP3 decoder for Kinetis MK64

oleglavrukhin — Mon, 16 Mar 2015 15:42:32 GMT

Hello, community!

I work with FRDM-K64F in CodeWarrior and KDS+KSDK. One part of my big project is a player WAV, MP3 and (may be) AAC and FLAC files.

Without any problem I make a WAV player (play files from USB stick and FLASH memory) based of example for SDK and MQX, it work finely in baremetal (KDS project) and with MQX (CW project).I get clear sound from external DAC (CS4350 from Cirrus logic) via I2S.

But I have a problem with software MP3 decoder.

I try to ported HELIX MP3 decoder from some projects for STM32. Decoder work (I try to use ASM and C realisations of Polyphase filter),

but in all variants sound have a DISTORTION!

The sound is very similar to roar (or crackles), or like a "overload" of the analog signal. This "roar" is heard only in the moments of the signal, during playback of silence at the beginning and end of the file there are no distortions.

I try to use example for Kinetis K-40, but get same distortions.:smileycry:

Can anyone share your implementation of software MP3 decoder for Kinetis?

Thank you for any help!

Oleg

Re: software MP3 decoder for Kinetis MK64

xiangjun_rong — Tue, 17 Mar 2015 08:46:30 GMT

Hi, Oleg,

It seems that your MP3 decoder has issue, maybe the PCM stream data from the decoder are saturated or incorrect. Do you have benchmark data which can generate correct PCM stream? After you decoder, you can compare the PCM data you decoded and the standard output.

XiangJun Rong

Re: software MP3 decoder for Kinetis MK64

oleglavrukhin — Tue, 17 Mar 2015 15:45:11 GMT

Hello, XiangJun Rong.

Can you explain in detail what should I do?

I try:

1) convert MP3 file (1kHz sine wave) into WAV via "Total Audio MP3 Converter"

2) save results of my Helix MP3 decoder in file

3) compare file from(1) with(2). they are different. i convert file (1) via "web online converter" and

get three three files with completely different content.

What are your proposals?

Regards, Oleg

Re: software MP3 decoder for Kinetis MK64

xiangjun_rong — Wed, 18 Mar 2015 03:04:59 GMT

Hi, Oleg,

Currently, you have to verify which result among the three result is correct. maybe you can log on MP official web site and seek the benchmark.

I never ported the MP code, but I think you have to consider the data format for example Q15 or Q31 or float, because the I2S data is 24 bits in general, you have to consider the data format conversion and truncation or saturation.

Hope it can give you a clue.

XiangJun Rong

Re: Re: software MP3 decoder for Kinetis MK64

oleglavrukhin — Wed, 18 Mar 2015 07:32:16 GMT

Hello, XiangJun Rong!

Thanks for You reply, but I would like to hear an audio expert advice. I attached WAV file, which i get after decoding. interference is very similar to the repetition frequency samples. I search in WEB, some people have similar problem, but no one offered to solve this problem

May be anybody have a worked example of MP3 player for Kinetis K64 (on CW or KDS)?

Regards,

Oleg

Re: software MP3 decoder for Kinetis MK64

oleglavrukhin — Sun, 10 May 2015 14:52:32 GMT

I solved the problem. Software MP3 decoder( i use Helix) produced (2*1152) bytes, but MQX SAI driver have a (2*512) bytes buffer as default. of course, I lost some decoded bytes when try send they into SAI buffer.

When I set SAI buffer size to "1152" (in BSP->BSP files->init_sai.c :

KSAI_INIT_STRUCT _bsp_ksai_init = {

0, /* Selected peripheral (HW channel) */

0, /* TX channel */

0, /* RX channel */

I2S_TX_ASYNCHRONOUS | /* TX is asynchronous */

I2S_RX_SYNCHRONOUS | /* RX hooked on TX */

I2S_TX_BCLK_NORMAL | /* Both TX and RX are clocked by the transmitter */

I2S_RX_BCLK_NORMAL, /* bit clock (SAI_TX_BCLK) */

I2S_TX_MASTER | /* SAI transmitter mode */

I2S_RX_MASTER, /* SAI receiver mode */

16, /* Data bits */

I2S_CLK_INT, /* Clock source */

FALSE, /* Tx Dummy */

5, /* Interrupt priority */

1152, /* Buffer size default setting is 512*/

CM_CLOCK_SOURCE_SYSTEM, /* Internal master clock source */

&_bsp_audio_data_init /* Audio init */

};

then i rebuild all the MQX lib's (BSP,PSP,MFS, RTCS, USB).

Now my MP3 decoder work correctly, sound is clear.

I hope my experience will be useful.

And i hope to find full descriptions for MQX i/o drivers in next release.

i can share my project(MQX mp3 usb player for FRDM-k64f) if someone will need to.

Re: software MP3 decoder for Kinetis MK64

niddem — Tue, 09 Jun 2015 05:12:42 GMT

Hi Oleg,

I have been working on the MP3 decoder using LibMad and have a working project using the Kinetis K70 with USB and SD with a 25-band spectrum analyzer on a 24-Bit RGB LCD with MQX 4.2. I am able to stream at 320kbps @ 16-bit. I am interested in your project using the Helix MP3 decoder to see the difference in performance. Could you send me your project?

Best Regards,

Bryan

Re: software MP3 decoder for Kinetis MK64

niddem — Wed, 10 Jun 2015 08:34:26 GMT

Hey,

Disregard my last post, I made an attempt to port in the Helix codec and I got it working. Took about two days, but I now have it integrated with my libMAD project. Its currently not utilizing DMA which is the next thing I am going to do to improve performance. The output is also on the DAC0 & DAC1 which I downsample the 16-but audio stream to 12-bit. Will be doing a stereo codec implementation with the SGTL5000 to get full audio quality output.

Regards,

Bryan

Re: software MP3 decoder for Kinetis MK64

alexquisi — Wed, 10 Jun 2015 11:54:51 GMT

Hi Oleg,

I am just starting to get MP3 working and it would be for me very useful to get your project as reference.

Could you please send it to my E-mail address: alexander_quinones AT hotmail DOT com?

Thanks in advance.

Regards,

Alex

Re: software MP3 decoder for Kinetis MK64

oleglavrukhin — Wed, 10 Jun 2015 14:24:36 GMT

Congratulations, Bryan! in my project I use external DAC CS4350 (Cirrus Logic), it work fine.

I'm intersting, how do You set SAI transmitt buffer size for SGTL5000 , as I have described, or you know another way?

Regards, Oleg

P.s. what IDE you use? i can't ported Libmad in Code Warrior 10.6 :smileyconfused:

Re: software MP3 decoder for Kinetis MK64

oleglavrukhin — Wed, 10 Jun 2015 14:34:46 GMT

Hi, Alexander.

i have 3 variants USB MP3 Player, based on Helix Decoder & Freescale MQX 4.1. For Codewarrior 10.6, IAR 7.2 and Keil uVision 5.

Projects have identical algorithm, but different files in Helix decoder library ( assembler implementation of Polyphase filter).

Which project do you want to receive?

Re: software MP3 decoder for Kinetis MK64

alexquisi — Wed, 10 Jun 2015 14:52:37 GMT

Hi Oleg,

thanks for your reply.

I am currently using KDS. Not sure which one of your versions will be easier to port/convert to KDS, maybe you have a better idea than me. As Bryan, I am also planning to connect my audio output with the SGTL5000.

It would be interesting to know his experience between Helix codec vs libMAD.

Thanks,

Alex

Re: software MP3 decoder for Kinetis MK64

oleglavrukhin — Wed, 10 Jun 2015 19:26:04 GMT

Hi, Alex!

i found my old project "USB mp3-wav player" in KDS2.0 + KSDK1.1. it work on FRDM-K64F with external DAC CS4350. You can try to use it, but You need remove my DAC driver and add driver for SGTL5000(or another DAC what you have).

Good Luck. !

Re: software MP3 decoder for Kinetis MK64

alexquisi — Thu, 11 Jun 2015 08:22:24 GMT

Hi Oleg,

thanks a lot!

I will give it a try in the next days ;-)

Best wishes,

Alexander

Re: software MP3 decoder for Kinetis MK64

niddem — Thu, 11 Jun 2015 16:59:14 GMT

Thanks Oleg! I am using IAR 7.2. I have Codewarrior 10.5 and could make an attempt to port LibMAD into there. Though the LibMAD decoded ouput is not the same as Helix. The pcm data is automatically separated into independent left/right channel buffers. (i.e. pcm[0][sample], pcm[1][sample]) as opposed to Helix which the data format is LRLR. I changed the transmit buffer size for the SAI module the same way you did in MQX under the KSAI_INIT_STRUCT _bsp_ksai_init structure. I was able to get the SGTL5000 codec working with WAV, some issues with crackling sounds. I am now working on integrating it into the MP3 project.

Re: software MP3 decoder for Kinetis MK64

niddem — Thu, 11 Jun 2015 17:04:27 GMT

Hi Alexander,

I haven't used KDS yet and am curious to know how well it works. I will keep you posted on my progress with the integration of the SGTL5000 codec with LibMAD and Helix.

Best Regards,

Bryan

Re: software MP3 decoder for Kinetis MK64

alexquisi — Fri, 12 Jun 2015 11:14:32 GMT

Hi Bryan,

This is my first project with the Kinetis MCU and I just selected KDS because it is free so I could not tell to much comparing it with other IDEs. Do you have some information about memory usage (RAM/ROM) and performance between LibMAD and Helix?

Though my initial project is a hobby, I was also reading about MP3 decoding licensing and theoretically the patent will expire at the end of this year but there could be some issues with the interpretation of the expiring date.

Have you get informed about the MP3 lisencing?

Thanks,

Alex

Re: software MP3 decoder for Kinetis MK64

niddem — Fri, 12 Jun 2015 17:35:20 GMT

Hi Alex,

I will be trying to use KDS in the near future to see how it functions.

The RAM/ROM requirement for LibMAD & Helix with optimization are:

LibMAD

2.67kB [RAM] / 54.6kB [ROM]

Helix

7.1kB [RAM] / 34.1kB [ROM] (RAM requirement can be reduced by making the input/output buffer smaller)

I haven't looked into the licensing of MP3 as I took on this project as a hobby.

Best Regards,

Bryan

Re: software MP3 decoder for Kinetis MK64

alexquisi — Tue, 16 Jun 2015 08:37:00 GMT

Hi Bryan,

thanks a lot for the useful information.

i'm looking forward to hearing from your progress with the SGTL5000 codec together with LibMAD and Helix.

Best wishes,

Alex

Re: software MP3 decoder for Kinetis MK64

oleglavrukhin — Thu, 18 Jun 2015 05:17:40 GMT

Hi, Bryan!

Can You share a part of your code with Libmad (Libmad library files and in-out functions)?
Because my Libmad project don't work (at program start i init SAI and get "devicei_ptr", but when Libmad execute "mad_synth_mute()", i lost "devicei_ptr" and can't write to SAI. I make Libmad project based on my Helix project - i use some functions for work with SAI module and external DAC).

at second, Libmad library have a "imdct_l_arm.S" file, but IAR return many error for this file. i found Libmad implementation without this file (in PIC32 project). maybe this library is incorrect?

Regards, Oleg