2008-07-12 05:11:18 G729 encode problem

hong li (CHINA)

Message: 58717

everyone, I am using g729 library on my bf561, I have test the libbrary successfully, However there is a problem which puzzles me.

why the SINEA.BIT is larger than SINE.BIN?

the SINEA.BIT is the output file after encoding, SINEA.BIT is in the /test_data/g729a/std_out_en

the SINE.BIN is the original file , SINE.BIN is in the /test_data/g729a/std_in_en

generally , the file after encoding is much smaller than the orginal file.

Thanks

Hong

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2008-07-13 22:28:59 Re: G729 encode problem

Yi Li (CHINA)

Message: 58731

It may use unpaced mode - i.e, each bit is reprensented using a 16-bit word.

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2008-07-14 01:00:38 Re: G729 encode problem

hong li (CHINA)

Message: 58742

because we want to send the audio data by the wireless network and the original audio data is too large, therefor, the original audio data must be compressed .

How to use the packed mode ? How to compress the original data by the libbfgots ' API?

Thanks

Hong

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2008-07-14 01:43:33 Re: G729 encode problem

hong li (CHINA)

Message: 58743

I read the g729ab_test.c and find in the test_encoder founction, the orginial data is inst_pcm_buf[80], however, the output data after encoding is inst_index_buf[82], why?

if I want to compress the data, how to set the length of inst_index_buf?

the encode founction is: G729AB_ENC(inst_g729_enc_h, inst_pcm_buf, inst_index_buf);

the founction as follow:

int test_encoder(int mode, FILE *fin, FILE *fbit, float *av_mips, int multi, int thread_id)

{

G729_EncObj inst_g729_enc __attribute__ ((aligned (4)));

G729_enc_h inst_g729_enc_h __attribute__ ((aligned (4)));

short inst_pcm_buf[80] __attribute__ ((aligned (4)));

short inst_index_buf[82] __attribute__ ((aligned (4)));

short result_buf[82];

int frame_num = 0;

int i = 0;

int len;

int before, time;

memset(&inst_pcm_buf, 80 * 2, 0);

memset(&inst_index_buf, 82 * 2, 0);

/* Init encoder */

inst_g729_enc_h = &inst_g729_enc;

(*g729ab_enc_reset) (inst_g729_enc_h);

G729AB_ENC_CONFIG(inst_g729_enc_h, G729_ENC_OUTPUTFORMAT, 1);

G729AB_ENC_CONFIG(inst_g729_enc_h, G729_ENC_VAD, mode);

time = 0;

while ((fread(inst_pcm_buf, 2, 80, fin) == 80)) {

//fprintf(stderr, "thread: %d - frame: %d\n", thread_id, frame_num);

before = cycles();

G729AB_ENC(inst_g729_enc_h, inst_pcm_buf, inst_index_buf);

time += cycles() - before;

/* simulate "hurry up and wait" of real time systems when

testing in multi-threaded mode */

if (multi) usleep(10000);

/* Verify */

if (mode) {

len = fread_a_frame(fbit, result_buf);

} else {

len = fread(result_buf, sizeof(short), 82, fbit);

}

for (i=0; i<len; i++) {

if (result_buf[i] != inst_index_buf[i]) {

fprintf(stderr, "diff:%d %hx, %hx\n",

frame_num*82 + i, inst_index_buf[i], result_buf[i]);

return -1;

}

frame_num++;

}

*av_mips = (float)(time/frame_num)*(FRAMES_PER_SEC/1E6);

return 0;

}

Thanks

Hong

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2008-07-14 04:13:05 Re: G729 encode problem

Yi Li (CHINA)

Message: 58748

If you read the README.txt in libbfgdots/g729/, you will read:

Bitstream formats:

using 0x6b21 as SYNC word for each frame

[SYNCWORD][BIT_NUM][bits]

Packed mode:

- g729a:

[0x6b21][0x0050][80-bit]

- g729ab:

three kinds of frames

-- BIT_NUM = 0x0050

-- BIT_NUM = 0x0010

-- BIT_NUM = 0x0000

Unpacked mode:

each bit is encoded using a 16-bit word:

- 0x007F for 0

- 0x0081 for 1

To use packed format:

G729AB_ENC_CONFIG(inst_g729_enc_h, G729_ENC_OUTPUTFORMAT, 0);

to use unpacked format:

G729AB_ENC_CONFIG(inst_g729_enc_h, G729_ENC_OUTPUTFORMAT, 1);

You can refer to: uclinux-dist/user/blkfin-apps/linphone/g729_patch

for some real example of using g729 lib in linphone.

However, we tested linphone with some VoIP phones, the format of those phones is a little different. You can read the patch for details. They do not use header, and they do not use packed mode.

If your g729 decoder and encoder both uses libbfgdots, you can use the packed mode, but it may not talk with other g729 clients.

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2008-07-14 21:12:52 Re: G729 encode problem

hong li (CHINA)

Message: 58772

My encoder and decoder both uses libbfgots, because the output data is 0x007f or 0x0081, I use one bit to represent the 0x007f or 0x0081, then, the output data is smaller than the orginial data, However, the effect of decoding is not good, I will try the packed mode.

Thanks your help

Hong

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2008-07-18 02:13:04 Re: G729 encode problem

hong li (CHINA)

Message: 59053

Thanks your help , I can use the packed mode to compress the audio data successfully

Hong