vstream (video stream) implementation and sample

[bennylp]

• Either extend existing stream.c to support video, or create a new vstream.c.
• Use vstreamutil.c as demo.

There is already video stream implementation in the stream.c and sample in the vstreamutil.c, however it's just proof-of-concept version, so the to do/consider list will be:

• proper picture bitstream generation from RTP packet, currently the video stream will just 'concatenate' incoming RTP to get a complete picture bitstream, and everytime it got end-of-picture flag, RTP header m==1, push the picture into jitter buffer, so in case of unordered RTP the picture bitstreams will be truncated
• perhaps jitter buffer frame content/granularity should be RTP payload instead of a picture bitstream (picture bitstream will be generated right before decoding, instead of inline with incoming RTP packets), however current jitter buffer only has RTP sequence (no RTP timestamp), so need to research if the current jitter buffer fits this requirements along with optimization consideration (e.g: frame size, minimal memcpy)
• audio-video sync
• encoder & decoder size can be different, e.g: remote endpoint, which is an embedded/mobile, only supports QCIF while local endpoint, which is desktop, prefers CIF, so the issues will be:
  • which size should be put in the stream info (as currently it only has one 'format info' field)?
  • the decoder output format (e.g: format id & size) can only be ensured after a successful picture decoding (the format setting in opening the decoder is rather unusable and the local SDP may offer multiple sizes), need a way to notify application about the active format.

[nanang]

(In [3418]) Re #1182: Reverted back video part in stream.h/c

[nanang]

(In [3420]) Re #1182:

• Added video stream interface in vid_stream.h, the video stream will be able to handle different video formats in encoding and decoding direction.
• Renamed video device stream class identifiers from 'pjmedia_vid_stream*' to 'pjmedia_vid_dev_stream*' as 'pjmedia_vid_stream' is used by video stream interface.
• Added ffmpeg video capability to be able to parse SDP format param for H263 and also decide video format for encoding direction based on remote preference and local format-capability setting.
• Added some new APIs in jitter buffer for handling video stream: pjmedia_jbuf_put_frame3(), pjmedia_jbuf_get_frame3(), pjmedia_jbuf_peek_frame(), and pjmedia_jbuf_remove_frame().
• Moved pjmedia_stream_info_from_sdp() from session to stream

[nanang]

(In [3425]) Re #1182:

• Renamed vstreamutil.c to vid_steamutil.c just for filename format consistency reason.
• Updated sample app simpleua.c and vid_streamutil.c to sync with updated API, e.g: strip session usage, two media ports exported video streams for each dir.
• Added vid_streamutil.c capability to be able to stream video file (involving transcoding when video codec used in the file different to the video stream codec), also updated AVI player and ffmpeg codecs to be able to read and decode XVID/MPEG4 codec.
• Fixed bug wrong media type check in stream.c and vid_stream.c in creating stream info from SDP.
• Minor update: docs, logs, app samples makefiles.

[ming]

(In [3431]) Re #1182:

• support for format modification after creating video port (currently for renderer with active role only).
• support for format modification after opening SDL renderer.

[nanang]

(In [3432]) Re #1182:

• Fixed ffmpeg codec: decoding buffer size check (should not use assertion), reset output bit_info before decoding, removed unused code of auto resize when decoder output size changed.
• Fixed bug in sdl_factory_default_param() of sdl_dev.c in device direction check.
• Fixed compile errors sample app vid_streamutil.c of bad local variable definiton.
• Updated sample app vid_streamutil.c default renderer size to 640 x 480.

[nanang]

(In [3435]) Re #1182:

• Added remote frame-rate detection in to video stream.
• Fixed bitrate settings in ffmpeg codec.
• Fixed SDL dev to update internal SDL info when format changed.
• Minor fixes/updates, e.g:
  • added cleanup steps, fixed logs, etc, in sample app simpleua.c and vid_streamutil.c
  • fixed/added docs of the new APIs in the jitter buffer.

[bennylp]

(In [3445]) Re #1182: added the video stream to pjmedia Makefile

[bennylp]

(In [3447]) Re #1182: renamed pjmedia_vid_stream to pjmedia_vid_dev_stream due to conflict with "the real" vid_stream

[bennylp]

(In [3513]) Re #1182:

• Removed RTCP-XR from video stream.
• Fixed few compile warnings on GCC for incompatible pointers.

[bennylp]

(In [3514]) Re #1182: fixed misc error with RTCP XR

[nanang]

(In [3534]) Re #1182: Added macro setting PJMEDIA_STREAM_RESV_PAYLOAD_LEN to let stream reserve some space for application extra data in the RTP payload, e.g: SRTP auth tag.

[nanang]

(In [3536]) Re #1182: Applied PJMEDIA_STREAM_RESV_PAYLOAD_LEN (see r3534) in stream.c.