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| 1 : | chl | 120 | EXAMPLES for usage of xvid_stat: |
| 2 : | |||
| 3 : | ********************************************************************************** | ||
| 4 : | |||
| 5 : | EXAMPLE 1 | ||
| 6 : | |||
| 7 : | $ xvid_stat < cactus.pgm | ||
| 8 : | |||
| 9 : | This calls xvid_stat with standard parameters for the 3 frames from the | ||
| 10 : | cactus file from examples directory. | ||
| 11 : | |||
| 12 : | Output should look similar to this: | ||
| 13 : | |||
| 14 : | Frame 0: intra 1, enctime = 4.7 ms length= 12470 bytes dectime = 4.2 ms PSNR 39.93 | ||
| 15 : | Frame 1: intra 0, enctime = 6.9 ms length= 1369 bytes dectime = 1.8 ms PSNR 40.40 | ||
| 16 : | Frame 2: intra 0, enctime = 6.6 ms length= 3354 bytes dectime = 2.3 ms PSNR 42.03 | ||
| 17 : | Avg. Q6 br 0900 (0.43 bpp) size 5731 (1146 kbps / 0.54 bpp) enc: 164.7 fps, dec: 362.0 fps | ||
| 18 : | PSNR P(2): 41.22 ( 40.40 , 42.03 ; 0.4698 ) I(1): 39.93 ( 39.93 , 39.93 ; 0.0000 ) | ||
| 19 : | |||
| 20 : | |||
| 21 : | The lines in detail: | ||
| 22 : | For every input frame one line is printed containing the data: | ||
| 23 : | |||
| 24 : | Frame the frame number, starting with 0 | ||
| 25 : | intra if the frame was encoded as I-frame (1) or P-frame (0), | ||
| 26 : | when B-frames are supported, they will get a value of 2 here. | ||
| 27 : | |||
| 28 : | enctime time for encoding this frame, in milliseconds (1/1000th of a second) | ||
| 29 : | length length of the MPEG-4 bitstream generated from this frame (in bytes) | ||
| 30 : | dectime time for decoding | ||
| 31 : | PSNR picture signal to noice ratio (a measurement of quality, higher is better) | ||
| 32 : | |||
| 33 : | then in the end, two status lines are printed, these can be used, e.g. for automatic | ||
| 34 : | quality tests: | ||
| 35 : | |||
| 36 : | Avg. indicated that we are now talking about average values | ||
| 37 : | Q6 quality parameter that was used (so here it was quality level 6) | ||
| 38 : | br 0900 bitrate mode was used with a bitrate of 900kbps the other possibility is "q" | ||
| 39 : | instead of "br", see another example | ||
| 40 : | size 5731 average size of an encoded frame | ||
| 41 : | 1146 kbps "real" bitrate that was achieved, it may differ from the bitrate given to the | ||
| 42 : | codec as a parameter, because this is real life | ||
| 43 : | 0.54 bpp number of bit per pixel for the encoding, useful when comparing videos of | ||
| 44 : | different size | ||
| 45 : | enc: 164.7 fps speed of encoding in frames per second | ||
| 46 : | dec: 362.0 fps speed of decoding in frames per second | ||
| 47 : | |||
| 48 : | ****************************************************************************************** | ||
| 49 : | |||
| 50 : | EXAMPLE 2 | ||
| 51 : | |||
| 52 : | $ xvid_stat 0 0 6 900 25 < cactus.pgm | ||
| 53 : | |||
| 54 : | This does exactly the same as above, but parameters | ||
| 55 : | quality = 6, | ||
| 56 : | bitrate = 900 | ||
| 57 : | framerate = 25 | ||
| 58 : | are provided instead of using default value. Output should be the same as in last example. | ||
| 59 : | Note that first and second parameter are 0, indicating that a PGM file should be read | ||
| 60 : | (which has a header that includes X and Y dimensions). | ||
| 61 : | |||
| 62 : | ****************************************************************************************** | ||
| 63 : | |||
| 64 : | $ xvid_stat 0 0 1 8 < cactus.pgm | ||
| 65 : | |||
| 66 : | Output: | ||
| 67 : | |||
| 68 : | Frame 0: intra 1, enctime = 4.1 ms length= 8420 bytes dectime = 3.4 ms PSNR 36.36 | ||
| 69 : | Frame 1: intra 0, enctime = 3.0 ms length= 659 bytes dectime = 1.5 ms PSNR 36.36 | ||
| 70 : | Frame 2: intra 0, enctime = 2.7 ms length= 595 bytes dectime = 1.5 ms PSNR 36.43 | ||
| 71 : | Avg. Q1 q 0008 (0.00 bpp) size 3224 ( 644 kbps / 0.31 bpp)enc: 304.3 fps, dec: 467.1 fps | ||
| 72 : | PSNR P(2): 36.40 ( 36.36 , 36.43 ; 0.0210 ) I(1): 36.36 ( 36.36 , 36.36 ; 0.0000 ) | ||
| 73 : | |||
| 74 : | This time, quality 1 is used, so output values are a little different. Since the fourth parameter | ||
| 75 : | (here 8) is smaller than 32, it is not considered as a bitrate value, but as a fixed quantizer. | ||
| 76 : | So in the "Avg." line there is a | ||
| 77 : | |||
| 78 : | q 0008 meaning "fixed quantizer mode" with quantizer 8. | ||
| 79 : | |||
| 80 : | |||
| 81 : | ****************************************************************************************** | ||
| 82 : | |||
| 83 : | $ xvid_stat 176 144 5 112 < foreman.qcif | ||
| 84 : | |||
| 85 : | This switches xvid_stat to RAW instead of PGM mode. The input is expected to be | ||
| 86 : | images of dimensions 176*144 in raw YUV 4:2:0 format. (So every image is exactly | ||
| 87 : | 38016 = 176*144 + 88*72 + 88*72 bytes in size). Some reference streams are in | ||
| 88 : | this format. Note that you MUST give correct dimensions, because they cannot be | ||
| 89 : | detected from the YUV material. | ||
| 90 : | Apart from this, the example uses quality 5 and a bitrate of 112 kbps with video speed | ||
| 91 : | of 30 frames per second (this is not encoding or decoding speed, but the speed at | ||
| 92 : | which the video would be played. This value is only important for ratecontrol...) | ||
| 93 : | |||
| 94 : |
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