[vlc] VLC H.264 decoder under packet loss scenario

[Neeraj Jayaswal]

Hi experts
I am newbie to streaming and codecs
Please forgive if the questions are naive
Does ffmpeg/libavcodec have error concealment in case of packet loss for a
H.264 stream.
I am running a stream with known packet losses and VLC player displays the
following messages



*main debug: adding playlist item `E:\Shailesh\H264_DePack_OLD\Copy of
H264_pkt_loss.264' ( E:\Shailesh\H264_DePack_OLD\Copy of H264_pkt_loss.264 )
main debug: creating new input thread
main debug: waiting for thread completion
main warning: drive letter E: found in source
main debug: `E:\Shailesh\H264_DePack_OLD\Copy of H264_pkt_loss.264' gives
access `' demux `' path `E:\Shailesh\H264_DePack_OLD\Copy of
H264_pkt_loss.264'
main debug: creating demux: access='' demux=''
path='E:\Shailesh\H264_DePack_OLD\Copy of H264_pkt_loss.264'
main debug: looking for access_demux module: 1 candidate
main debug: thread 3768 (input) created at priority 1
(src/input/input.c:230)
main debug: creating access '' path='E:\Shailesh\H264_DePack_OLD\Copy of
H264_pkt_loss.264'
main debug: looking for access2 module: 5 candidates
vcd debug: trying .cue file: E:\Shailesh\H264_DePack_OLD\Copy of
H264_pkt_loss.cue
access_file debug: opening file `E:\Shailesh\H264_DePack_OLD\Copy of
H264_pkt_loss.264'
main debug: using access2 module "access_file"
main debug: pre buffering
main debug: received first data for our buffer
main debug: prebuffering done 1408981 bytes in 0s - 374410 kbytes/s
main debug: creating demux: access='' demux=''
path='E:\Shailesh\H264_DePack_OLD\Copy of H264_pkt_loss.264'
main debug: looking for demux2 module: 40 candidates
ffmpeg debug: detected format: h264
main debug: selecting program id=0
ffmpeg debug: adding es: video codec = h264
ffmpeg debug: AVFormat supported stream
ffmpeg debug:     - format = h264 (raw H264 video format)
ffmpeg debug:     - start time = -1
ffmpeg debug:     - duration = -1
main debug: using demux2 module "ffmpeg"
main debug: looking for a subtitle file in E:\Shailesh\H264_DePack_OLD\
main debug: looking for decoder module: 26 candidates
ffmpeg debug: libavcodec initialized (interface 3276801 )
ffmpeg debug: postprocessing disabled
ffmpeg debug: ffmpeg codec (h264) started
main debug: using decoder module "ffmpeg"
main debug: thread 3868 (decoder) created at priority 0
(src/input/decoder.c:159)
main debug: `E:\Shailesh\H264_DePack_OLD\Copy of H264_pkt_loss.264'
successfully opened
main debug: no usable vout present, spawning one
main debug: window size: 144x176
main debug: looking for video output module: 5 candidates
vout_directx debug: creating DirectXEventThread
main debug: waiting for thread completion
vout_directx debug: DirectXCreateWindow
vout_directx debug: Created video sub-window
main debug: thread 3888 (DirectX Events Thread) created at priority 0 (
directx.c:261)
vout_directx debug: DirectXEventThread running
vout_directx debug: DirectXInitDDraw
vout_directx debug: directx-device:
vout_directx debug: DirectXEnumCallback: Primary Display Driver, display
vout_directx debug: screen dimensions (0x0,1024x768)
vout_directx debug: DirectDraw Capabilities: overlay=1 yuvoverlay=1
can_deinterlace_overlay=1 colorkey=1 stretch=1 bltfourcc=1
vout_directx debug: End DirectXInitDDraw
vout_directx debug: DirectXCreateDisplay
main debug: Registering subpicture channel, ID: 2
main debug: Registering subpicture channel, ID: 3
main debug: Registering subpicture channel, ID: 4
main debug: Registering subpicture channel, ID: 5
vout_directx debug: DirectXCreateClipper
main debug: using video output module "vout_directx"
main debug: waiting for thread completion
vout_directx debug: NewPictureVec overlay:yes chroma:YV12
vout_directx debug: YUV overlay created successfully
vout_directx debug: End NewPictureVec (succeeded)
main debug: got 1 direct buffer(s)
main debug: picture in 144x176 (0,0,144x176), chroma I420, ar 58909:72000,
sar 1:1
main debug: picture user 144x176 (0,0,144x176), chroma I420, ar 58909:72000,
sar 1:1
main debug: picture out 144x176 (0,0,144x176), chroma I420, ar 58909:72000,
sar 1:1
main debug: direct render, mapping render pictures 0-6 to system pictures
1-7
main debug: thread 3916 (video output) created at priority 1
(src/video_output/video_output.c:416)
main warning: late picture skipped (171614)
main warning: late picture skipped (131639)
main warning: late picture skipped (91648)
main warning: late picture skipped (57075)
main warning: late picture skipped (17096)*

**

what do the highlighted warnings mean. What do the numbers enclosed in the
brackets signify.





Thanks and regards

Neeraj
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