Hi,
My customer found an issue on MPEG-2 encoder for DM365. It is that green was added on some blocks in some frames(not only I frame, P frame also) by MPEG-2 encoder. This phenomenon can be seen on DM365 EVM also with simple MPEG-2 encoder application. When the file encoded by DM365 is decoded, you can find that green level become little bit bigger than input video image before encoding, by using any PC application software which can measure RGB level of pixel data.
Ex. Input image R=95:G=95:B=95 => Encoded image R=95:G=98:B=95
Have you seen this phenomenon ?
Could you check this issue ?
It is difficult to see this phenomenon on movie and/or on color image.
The attached file is a closeup image of ultrasonograph image. This image was changed brightness higher by PC application software at off line for easy to see.
Also, they tested to input monochrome video (set Cb = Cr = 128 (0x80) ) into CCDC on DM365 and checked some frames stored on SDRAM just before passing to encoder. Then, there was no green on these images, it was monochrome image (still Cb = Cr =0x80).
However, encoded video image had some blocks which green level become bigger little bit after encoding.
From these results, green seems to be added in some blocks of some frames by MPEG-2 encoder.
This issue occurred on both CBR and VBR.
It seems that this doesn’t depend on bitrate.
My customer has finished developing their system with MPEG-2 encoder on DM365. However, the image quality has rejected by their QA (Quality Assurance) division just before mass production.
Could you please help them.
For your reference, codec parameters are attached as follows. This is just one of parameter sets which they tested some cases. They tried VBR mode also with targetBitRate=9800 and maxBitRate=9799, then the same issue occurred.
== VIDENC1_Params =========
encodingPreset : 2
rateControlPreset : 1
maxHeight : 480
maxWidth : 720
maxFrameRate : 30000
maxBitRate : 4096000
dataEndianness : 1
maxInterFrameInterval: 1
inputChromaFormat : 9
inputContentType : 1
reconChromaFormat : 9
== IMP2VENC_Params ========
aspectRatio : 2
pixelRange : 1
timerResolution : 30
ME_Type : 1
QscaleType : 0
IntraDCPrec : 0
hdvicpHandle : (nil)
== VIDENC1_DynamicParams ==
inputHeight : 480
inputWidth : 720
refFrameRate : 30000
targetFrameRate : 30000
targetBitRate : 4096000
intraFrameInterval : 5
generateHeader : 0
captureWidth : 1440
forceFrame : -1
interFrameInterval : 0
mbDataFlag : 0
Best regards,
Hideaki
