Results 1 to 5 of 5

Thread: Poor transcode quality

  1. #1

    Default Poor transcode quality

    Hi,

    We are taking a live rtsp input (720p 5fps) and transcoding to 2 resolutions - 720p (with KeyFrameInterval different than input) and 360p. I have tried encoding with mainconcept encoder and NVENC encoders (on NVIDIA grid K520) at sufficiently high bitrates, but get very poor quality video output. I observed video artifacts at exact same locations when encoded with both mainconcept and NVENC encoders, which makes me believe the decoded video output (just before encoding) must be poor.

    Is there anyway i can tweak the video decoding parameters to improve the video quality?

    Thanks,
    Rakshith

  2. #2

    Default

    Do you see any messages like this in the access log?
    TranscodingSession.updateBehindFilter[transcoder/_definst_/myStream]: Video behind filter state change. New state: SKIP1FRAME
    TranscodingSession.updateBehindFilter[transcoder/_definst_/myStream]: Video behind filter state change. New state: ALLFRAMESON
    If so, this means that machine is not keeping up with transcoding. Take a look at the Transcoder Benchmarks to get an idea of server capabilities and limitations.

    Regards,

    Salvadore

  3. #3

    Default

    No i don't see above messages in the logs. We are running these tests (single 720p input transcoded to two outputs - 720p and 360p) on EC2 g2.2x large. As per the transcoder benchmark,g2.2x large can handle much higher capacity than what we are testing

    Regards,
    Rakshith

  4. #4

    Default

    Figured out the issue. We are using ffmpeg to push rtsp stream to wowza and it is transcoding the input video file by default. Preventing ffmpeg from transcoding improved the video quality

    Regards,
    Rakshith

  5. #5

    Default

    Thank you for the update on this. Glad to hear you sorted this out.

    Regards,

    Salvadore

Similar Threads

  1. rtsp stream quality poor
    By pmeeke in forum Performance and Tuning
    Replies: 5
    Last Post: 07-26-2014, 12:50 AM
  2. Live record file has very poor quality
    By coskel22 in forum Live Streaming and Encoder Discussion
    Replies: 4
    Last Post: 05-27-2012, 12:14 PM
  3. Wirecast poor quality and good quality live flash
    By dj_carpio in forum Live Streaming and Encoder Discussion
    Replies: 3
    Last Post: 04-17-2012, 05:36 PM
  4. Poor video quality (wowza + wirecast + jwplayer)
    By ecorderob in forum Live Streaming and Encoder Discussion
    Replies: 1
    Last Post: 04-16-2012, 03:15 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •