[alsa-devel] [tinycompress]how should I call compress_open for aac ltp file playback?
I am trying to use tinycompress for hwdecoder. everything works fine, but after compress_open (with profile = SND_AUDIOPROFILE_AAC level=0 ch_mode=0 rate_control=0), the playback of my aac-ltp-16bit-48KHz-Stereo file is faster than it should be. Am I wrong?
struct snd_codec { __u32 id; __u32 ch_in; __u32 ch_out; __u32 sample_rate; __u32 bit_rate; __u32 rate_control; __u32 profile; __u32 level; __u32 ch_mode; __u32 format; __u32 align; union snd_codec_options options; __u32 reserved[3]; };
Keyon
On Wed, Jun 05, 2013 at 02:46:04PM +0800, Keyon.Jey wrote:
I am trying to use tinycompress for hwdecoder. everything works fine, but after compress_open (with profile = SND_AUDIOPROFILE_AAC level=0 ch_mode=0 rate_control=0), the playback of my aac-ltp-16bit-48KHz-Stereo file is faster than it should be. Am I wrong?
Vinod is probably the person for this one, as I am not so familiar with what you guys have done internally. However, my guess would be you are not setting the sample_rate correctly? It likely needs to be set to the appropriate SNDRV_PCM_RATE_XXXX define. The source for cplay included in the tinycompress repository is a good example of using the tinycompress library.
Charles
On 06/05/2013 04:01 PM, Charles Keepax wrote:
On Wed, Jun 05, 2013 at 02:46:04PM +0800, Keyon.Jey wrote:
I am trying to use tinycompress for hwdecoder. everything works fine, but after compress_open (with profile = SND_AUDIOPROFILE_AAC level=0 ch_mode=0 rate_control=0), the playback of my aac-ltp-16bit-48KHz-Stereo file is faster than it should be. Am I wrong?
Vinod is probably the person for this one, as I am not so familiar with what you guys have done internally. However, my guess would be you are not setting the sample_rate correctly? It likely needs to be set to the appropriate SNDRV_PCM_RATE_XXXX define. The source for cplay included in the tinycompress repository is a good example of using the tinycompress library.
Charles _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
thanks, Charles. the print log showed me that I have set SNDRV_PCM_RATE_48000 which seems no problem. the cplay example code is only for mp3 file, and it also not set .level, .ch_mode and .rate_control. Vinod, what's your suggestion?
thanks, Keyon
On Wed, Jun 05, 2013 at 04:27:44PM +0800, Keyon.Jey wrote:
On 06/05/2013 04:01 PM, Charles Keepax wrote:
On Wed, Jun 05, 2013 at 02:46:04PM +0800, Keyon.Jey wrote:
I am trying to use tinycompress for hwdecoder. everything works fine, but after compress_open (with profile = SND_AUDIOPROFILE_AAC level=0 ch_mode=0 rate_control=0), the playback of my aac-ltp-16bit-48KHz-Stereo file is faster than it should be. Am I wrong?
Vinod is probably the person for this one, as I am not so familiar with what you guys have done internally. However, my guess would be you are not setting the sample_rate correctly? It likely needs to be set to the appropriate SNDRV_PCM_RATE_XXXX define. The source for cplay included in the tinycompress repository is a good example of using the tinycompress library.
thanks, Charles. the print log showed me that I have set SNDRV_PCM_RATE_48000 which seems no problem. the cplay example code is only for mp3 file, and it also not set .level, .ch_mode and .rate_control. Vinod, what's your suggestion?
You need to ask your firmware guys, what are they expecting the these fields. Some decoder implementations can be different. But i would expect the audio to be broken, bad quality if that is the case.
But the speed of playback can be due to different decoder output rate and different sampling rate configured. You are telling decoder 48Khz as CPM sample rate, is that what decoder is understanding and conversion to decoder values correct. Then you should check if the rendering to DAC is at 48KHz or not.
-- ~Vinod
On 06/07/2013 08:23 AM, Vinod Koul wrote:
On Wed, Jun 05, 2013 at 04:27:44PM +0800, Keyon.Jey wrote:
On 06/05/2013 04:01 PM, Charles Keepax wrote:
On Wed, Jun 05, 2013 at 02:46:04PM +0800, Keyon.Jey wrote:
I am trying to use tinycompress for hwdecoder. everything works fine, but after compress_open (with profile = SND_AUDIOPROFILE_AAC level=0 ch_mode=0 rate_control=0), the playback of my aac-ltp-16bit-48KHz-Stereo file is faster than it should be. Am I wrong?
Vinod is probably the person for this one, as I am not so familiar with what you guys have done internally. However, my guess would be you are not setting the sample_rate correctly? It likely needs to be set to the appropriate SNDRV_PCM_RATE_XXXX define. The source for cplay included in the tinycompress repository is a good example of using the tinycompress library.
thanks, Charles. the print log showed me that I have set SNDRV_PCM_RATE_48000 which seems no problem. the cplay example code is only for mp3 file, and it also not set .level, .ch_mode and .rate_control. Vinod, what's your suggestion?
You need to ask your firmware guys, what are they expecting the these fields. Some decoder implementations can be different. But i would expect the audio to be broken, bad quality if that is the case.
But the speed of playback can be due to different decoder output rate and different sampling rate configured. You are telling decoder 48Khz as CPM sample rate, is that what decoder is understanding and conversion to decoder values correct. Then you should check if the rendering to DAC is at 48KHz or not.
-- ~Vinod
thanks, Vinod, I will check with the firmware guys for these detail fields.
~Keyon
participants (3)
-
Charles Keepax -
Keyon.Jey -
Vinod Koul