Manipulate data between omxmjpegdec and omxh264enc with a fifo on PI 3?

[justyoung17]

Hi,

Not sure if it makes sense about what I tried to do, for example, below worked fine as I was able to pipe in mjpeg from the IP camera on raspi3 to an external rtmp channel:

ffmpeg -i "rtsp://xxxx" -vcodec copy -f mjpeg -y - | \
gst-launch-1.0 \
-v fdsrc fd=0 \
! "image/jpeg,width=1280, height=720,framerate=25/1" \
! jpegparse \
! omxmjpegdec \
! omxh264enc \
! h264parse \
! queue \
! flvmux streamable=true \
! queue \
! rtmpsink location="rtmp://yyyy"

However, when I placed a fifo between omxmjpegdec and omxh264enc

For example

Session 1:

mkfifo

ffmpeg \
-i "rtsp://xxxx" -vcodec copy -f mjpeg -y - | \
gst-launch-1.0 \
-v fdsrc fd=0 \
! "image/jpeg,width=1280, height=720,framerate=25/1" \
! jpegparse \ ! omxmjpegdec \ ! filesink location=myfifo

And Session 2:

tail -F myfifo |
gst-launch-1.0 \
-v fdsrc \
! omxh264enc \
! h264parse \
! queue \
! flvmux streamable=true \
! queue \
! rtmpsink location="rtmp://yyyy"


Session 2 hung on 'Pipeline is PREROLLING...'. I could see session 1 worked fine as it did keep feeding data to the fifo. I am guessing maybe in session 2 I need to provide perhaps some sort of data format before it gets chaining into omxh264enc; I inserted "video/x-raw,width=1280, height=720,framerate=25/1" but no luck. Reason for placing a fifo is basically a trial to see whether I could manipulate the data before piping into omxh264enc, and I am stuck already in first step with fifo so perhaps such approach isn't going to work and I just wanted to know so I can start looking around other approach.

Many thanks and hope someone could help here.

[Mikl]

Hello, 

Try to look on probe.

You can drop from stream.

Mikl

---

From: gstreamer-devel <[hidden email]> on behalf of justyoung17 <[hidden email]>
Sent: Sunday, February 5, 2017 8:51:05 PM
To: [hidden email]
Subject: Manipulate data between omxmjpegdec and omxh264enc with a fifo on PI 3?

 

Hi,

Not sure if it makes sense about what I tried to do, for example, below worked fine as I was able to pipe in jmpeg from the IP camera on raspi3 to an external rtmp channel:

ffmpeg -i "rtsp://xxxx" -vcodec copy -f mjpeg -y - | \
gst-launch-1.0 \
-v fdsrc fd=0 \
! "image/jpeg,width=1280, height=720,framerate=25/1" \
! jpegparse \
! omxmjpegdec \
! omxh264enc \
! h264parse \
! queue \
! flvmux streamable=true \
! queue \
! rtmpsink location="rtmp://yyyy"

However, when I placed a fifo between omxmjpegdec and omxh264enc

For example

Session 1:

mkfifo

ffmpeg \
-i "rtsp://xxxx" -vcodec copy -f mjpeg -y - | \
gst-launch-1.0 \
-v fdsrc fd=0 \
! "image/jpeg,width=1280, height=720,framerate=25/1" \
! jpegparse \ ! omxmjpegdec \ ! filesink location=myfifo

And Session 2:

tail -F myfifo |
gst-launch-1.0 \
-v fdsrc \
! omxh264enc \
! h264parse \
! queue \
! flvmux streamable=true \
! queue \
! rtmpsink location="rtmp://yyyy"


Session 2 hung on 'Pipeline is PREROLLING...'. I could see session 1 worked fine as it did keep feeding data to the fifo. I am guessing maybe in session 2 I need to provide perhaps some sort of data format before it gets chaining into omxh264enc; I inserted "video/x-raw,width=1280, height=720,framerate=25/1" but no luck. Reason for placing a fifo is basically a trial to see whether I could manipulate the data before piping into omxh264enc, and I am stuck already in first step with fifo so perhaps such approach isn't going to work and I just wanted to know so I can start looking around other approach.

Many thanks and hope someone could help here.

---

View this message in context: Manipulate data between omxmjpegdec and omxh264enc with a fifo on PI 3?
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[Tim Müller]

On Sun, 2017-02-05 at 11:51 -0800, justyoung17 wrote:

Hi,

you fifo is probably stream-based, so it will destroy the packetisation of the decoded video data where 1 buffer = 1 frame = certain constant/fixed amount of bytes, which is what an h264 encoder will expect.

Cheers

-Tim

-- 

Tim Müller, Centricular Ltd - http://www.centricular.com

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