H264 Encoded with much larger file size or much lower quality

[dzhou_tac]

Hi,

I decoded an h264 transport stream into YUV420, then encoded it into H264 with umc_video_encoder.exe. But I found the file size is much larger than the original.

The encoder uses 5000000 bits per second. It generates the same quality h264 stream as original. But the file size is 22148 bytes per frame. While the original is 7515 bytes per frame.

If I set bit rate to 2000000 bits per second. Then it generates much degrated quality h264 with 7427 bytes per frame.

thanks,

david

[Tamer_Assad]

Quoting dzhou.tac

Hi,

I decoded an h264 transport stream into YUV420, then encoded it into H264 with umc_video_encoder.exe. But I found the file size is much larger than the original.

The encoder uses 5000000 bits per second. It generates the same quality h264 stream as original. But the file size is 22148 bytes per frame. While the original is 7515 bytes per frame.

If I set bit rate to 2000000 bits per second. Then it generates much degrated quality h264 with 7427 bytes per frame.

thanks,

david

Hi David,

please check the following:

1. resolution (w*h) of the both original and product streams

2. frame rate(fps) of the both original and product streams

which encoder was used to encode the original stream?

do you know what is the original stream bit-rate?

Regards,

Tamer

[dzhou_tac]

Hi Tamer,

the resolution w*h and frame per seconds are the same. I also generated m2 file, and m4 file.

The sizes are:

m2=6,131KB, m4=6,336 KB, and H264 =6,252KB for the same number of frames (289 frame).

The original stream =2.071KB.

Thanks,

david