Hi, see below for a some comments. Hans Verkuil wrote: > RFC MPEG encoding and decoding V4L2/DVB API additions > Version 0.3 > ... > MPEG Decoding commands > ---------------------- > > In this section I will examine how to implement the decoding > functionality of the conexant cx23415 in terms of the DVB API, and > what, if any, additions to that API are needed to support it fully. > > 1) Start/Stop/Pause/Resume decoding > > After discussing this with Ralph it became clear that it was best to add > two new ioctls (as designed in the first version of this RFC) since the > existing VIDEO_PLAY/STOP/FREEZE/CONTINUE did not provide the required > functionality. The existing ioctls can still be used, but only do the > simple action. For more refined control (and better support for future > extensions) new VIDEO_COMMAND and VIDEO_TRY_COMMAND ioctls are added. > This ensures that existing apps won't break, but that the cx23415 is > still fully supported. Also future extensions are much easier. > > #define VIDEO_CMD_PLAY (0) > #define VIDEO_CMD_STOP (1) > #define VIDEO_CMD_FREEZE (2) > #define VIDEO_CMD_CONTINUE (3) > > /* Flags for VIDEO_CMD_CONTINUE */ > #define VIDEO_CMD_PAUSE_TO_BLACK (1 << 0) > > /* Flags for VIDEO_CMD_STOP */ > #define VIDEO_CMD_STOP_TO_BLACK (1 << 0) > > /* Flags for VIDEO_CMD_PLAY */ > #define VIDEO_CMD_PLAY_SPEED_MUTE_AUDIO (1 << 0) Hm - is this really necessary? The application could simply use AUDIO_SET_MUTE instead. > ... > 5) Audio mode selection > > The cx23415 allows automatic selection of the audio mode (stereo, left, > right, mono or swapped channels) for both a normal stereo capture and a > bilingual capture. > > The AUDIO_CHANNEL_SELECT ioctl comes close. If the > audio_channel_select_t enum was extended with AUDIO_MONO and > AUDIO_STEREO_SWAPPED and a AUDIO_BILINGUAL_CHANNEL_SELECT ioctl was > added, then this would fully implement this feature. How is AUDIO_BILINGUAL_CHANNEL_SELECT supposed to work? The av7110 driver uses AUDIO_MONO_LEFT/AUDIO_MONO_RIGHT to select the channel. CU Oliver -- -------------------------------------------------------- VDR Remote Plugin 0.3.9 available at http://www.escape-edv.de/endriss/vdr/ -------------------------------------------------------- _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
