The Linux distribution of imx6

[Mihan]

Could somebody tell me the distribution of imx6?

Cus I have some question about Qt media player. Or could someone tell me how to solve this problem:

defaultServiceProvider::requestService(): no service found for - "org.qt-project.qt.mediaplayer"

[Rita_Wang]

All the linux BSP released in our website, you can see them. About your question, could you tell us more information, which board and bsp are you using.

https://community.nxp.com/docs/DOC-94066?sr=search&searchId=48cdb04c-a64d-49a1-b57e-15839597c6b3&sea... This is for old BSP.

[Mihan]

Hello b45499‌, these days I tried using alsa to play WAV file. On ubuntu desktop, it works well. But on the device,it doesn't work, with error message when snd_pcm_hw_params:

format=0x1, channels=0x1,sample_fq=8000,byte_p_sec=16000,byte_p_sample=2,bit_p_sample=16
pcm_data_size=0x2f18
hw_params: format=2, channels=1
set hw params error:Invalid argument

there is the code:

int CSound::PlayWAVFile(QString path)
{
int i, fd;
int ret, dir, size;
unsigned int val, val2;
char* buffer;
snd_pcm_t* handle;
snd_pcm_hw_params_t* params;
snd_pcm_uframes_t periodsize;
snd_pcm_uframes_t frames;
HWParams hw_params;
// if(argc<2)
// {
// qDebug("usage ./play ");
// return -1;
// }
fd = open(path.toLatin1().data(), O_RDWR);
if(fd<0)
{
qDebug("file open error");
return -1;
}
Check_WAVFile(fd, &hw_params); //从wav头中分析出的参数，保存在hw_param中

if( (ret = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0)) < 0)
{
qDebug("open pcm device error:%s", snd_strerror(ret));
return -1;
}

snd_pcm_hw_params_alloca(&params);
snd_pcm_hw_params_any(handle, params);
snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
//snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE); //last param get from wav file
snd_pcm_hw_params_set_format(handle, params, hw_params.format);

//snd_pcm_hw_params_set_channels(handle, params, 2);
snd_pcm_hw_params_set_channels(handle, params, hw_params.channels); //last param get from wav file
qDebug("hw_params: format=%d, channels=%d", hw_params.format, hw_params.channels);

val = 44100;
snd_pcm_hw_params_set_rate_near(handle,params, &val, &dir);

frames = 32*4;
snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir);
//3. set param to driver
if((ret=snd_pcm_hw_params(handle, params)) < 0)
{
qDebug("set hw params error:%s", snd_strerror(ret));
return -1;
}

snd_pcm_hw_params_get_period_size(params, &frames, &dir);
size = frames*4; //2byte/smaple, 2 channels
buffer = (char*)malloc(size);

snd_pcm_hw_params_get_period_time(params, &val, &dir);
while(1)
{
ret = read(fd, buffer, size); 
if(ret==0)
{
qDebug("end of file");
// return 0;
break;
}else if (ret!=size)
{
qDebug("short read");
}

ret = snd_pcm_writei(handle, buffer, frames); 
if(ret == -EPIPE)
{
//qDebug("-EPIPE");
snd_pcm_prepare(handle);
}
}

snd_pcm_drain(handle);
snd_pcm_close(handle);
free(buffer);
return EXIT_SUCCESS;
}

int CSound::Check_WAVFile(int fd, HWParams* hw_params)
{
int ret;
int i, len;
WaveHeader* header;
WaveFmtBody* fmt;
WaveChunkHeader* chunk_header;
unsigned char* pbuf = (unsigned char*)malloc(128);
if(NULL == pbuf)
{
qDebug("pbuf malloc error");
return -1;
}
//1. check Wave Header
len = sizeof(WaveHeader);
if( (ret=read(fd, pbuf, len)) != len)
{
qDebug("read error");
return -1;
}
header = (WaveHeader*)pbuf;
if( (header->magic!=WAV_RIFF) || (header->type!=WAV_WAVE))
{
qDebug("not a wav file");
return -1;
}
//2. check Wave Fmt
len = sizeof(WaveChunkHeader)+sizeof(WaveFmtBody);
if( (ret=read(fd, pbuf, len)) != len)
{
qDebug("read error");
return -1;
}
chunk_header = (WaveChunkHeader*)pbuf;
if( chunk_header->type!=WAV_FMT)
{
qDebug("fmt body error");
return -1;
}
fmt = (WaveFmtBody*)(pbuf+sizeof(WaveChunkHeader));
if(fmt->format != 0x0001) //WAV_FMT_PCM
{
qDebug("format is not pcm");
return -1;
}
qDebug("format=0x%x, channels=0x%x,sample_fq=%d,byte_p_sec=%d,byte_p_sample=%d,bit_p_sample=%d",
fmt->format, fmt->channels,fmt->sample_fq, fmt->byte_p_sec,
fmt->byte_p_spl, fmt->bit_p_spl);
//copy params
hw_params->channels = fmt->channels;
hw_params->rate = fmt->sample_fq;
switch(fmt->bit_p_spl)
{
case 8:
hw_params->format = SND_PCM_FORMAT_U8;
break;
case 16:
hw_params->format = SND_PCM_FORMAT_S16_LE;
break;
default:
qDebug("FIXME: add more format");
break;
}
//3. check data chunk
len = sizeof(WaveChunkHeader);
if( (ret=read(fd, pbuf, len)) != len)
{
qDebug("read error");
return -1;
}
chunk_header = (WaveChunkHeader*)pbuf;
if(chunk_header->type != WAV_DATA)
{
qDebug("not data chunk");
return -1;
}
qDebug("pcm_data_size=0x%x",chunk_header->length);

free(pbuf);
pbuf = NULL;
return -1;
}

[Mihan]

Hi~ I'm so sorry that I didn't reply until now.

I have made a new topic https://community.nxp.com/thread/512276. But I still don't understand it.

What is the relationship between the interface and GStreamer or PulseAudio.

I just want to play a music by Qt. T^T

Does it mean I should rebuild the linux kernel or the Qt for Arm?

Thank you so much for your help.