Hi There, I am having a problem with getting an audio stream present in the MPEG2 stream from an HVR-1300 card. Background ~~~~~~~~~ I am using an HVR-1300 card in a Linux system running 2.6.28.6 vanilla kernel and using latest v4l2 drivers from the repository. We are trying to use the onboard MPEG H/W encoder CX23416 to deliver an MPEG-2 stream with both audio and video. To test I capture using "cat /dev/video1 > test.mpg" and I am using mplayer to play the subsequently captured stream. Problem ~~~~~~ The delivered MPEG-2 stream generally has no audio component. Mplayer reports "no audio found". The same problem exists for both TV input and composite input. By repeatedly switching between the TV input and the Composite input we can eventually get an audio component in the MPEG-2 stream. Thereafter we always get the audio component until a power off and restart. Simply rebooting (no power off) seems to still leave things in a state where the audio component is in the MPEG-2 stream. There is a second problem, the audio stream always contains white noise (I assume TV tuner noise - we don't have it tuned nor an aerial attached) mixed with the signal applied to the analog in ports. Analysis ~~~~~~ The most likely scenario is that the hardware is not being initialised correctly most of the time, once it is initialised correctly then it works thereafter. Unfortunately it is difficult to determine the actual audio path being used. Clearly the audio comes into the WM8775 (DAC) via a bus switch that switches between the composite/audio on the back panel and the white header. It then enters the CX2388x via the I2S input pins. We initially assumed that the audio was then routed through to the CX23416 (MPEG Encoder) via the I2S output pins of the CX2388x, but we have begun to doubt this assumption since the CX2388x is set in normal mode by the drivers and the captured audio doesn't reflect the bit patterns we see on the I2S Data Out line using an oscilloscope. That is, when we apply *no* signal to the analog input, the I2S Dout line is "quiet" yet we hear white noise. Questions ~~~~~~~~ 1) Anyone have any similar experiences? 2) Does anyone have more information on the "blackbird reference design", in particular can the CX2388x be configured into passthrough mode so the I2S from the WM8775 goes directly to the CX23416. I think the current wiring configuration of the CX23416 to the CX2388x precludes this? 3) How might the analog signal be being routed to the CX23416 for encoding if not via the I2S input? Kind regards Shane Harrison Paragon Electronic Design NZ -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
