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| 1 : | edgomez | 562 | +--------------------------------------------------------------------+ |
| 2 : | | XviD core lib examples | | ||
| 3 : | +--------------------------------------------------------------------+ | ||
| 4 : | |||
| 5 : | Isibaar | 3 | In this directory can find some examples how to use XviD MPEG4 codec |
| 6 : | in your own programs. | ||
| 7 : | |||
| 8 : | edgomez | 562 | ** cactus.pgm.bz2 |
| 9 : | ---------------------------------------------------------------------- | ||
| 10 : | Isibaar | 3 | |
| 11 : | edgomez | 562 | This a test sequence of 3 images with a cactus moving from right to |
| 12 : | left. It bzip2-compressed for size reason (half the size of a | ||
| 13 : | ZIP-file). Binaries of bunzip2 are available for all major OSes at | ||
| 14 : | http://sources.redhat.com/bzip2/ The original source of the cactus | ||
| 15 : | image is unknown... | ||
| 16 : | Isibaar | 3 | |
| 17 : | edgomez | 562 | * xvid_encraw.c |
| 18 : | ---------------------------------------------------------------------- | ||
| 19 : | Isibaar | 3 | |
| 20 : | edgomez | 562 | This is a small example that allows you to encode YUV streams or PGM |
| 21 : | files into a MPEG4 stream. It can output single files (on per encoded | ||
| 22 : | frame), or one file for all the enced stream (m4v format or a simple | ||
| 23 : | container format that we called mp4u, its description can be found at | ||
| 24 : | the end of this file). This program also outputs some very basic time | ||
| 25 : | results. | ||
| 26 : | Isibaar | 3 | |
| 27 : | edgomez | 562 | Type "xvid_encraw -help" to have all options' description. |
| 28 : | Isibaar | 3 | |
| 29 : | edgomez | 562 | Examples : |
| 30 : | Isibaar | 3 | |
| 31 : | edgomez | 562 | 1) bzip2 -dc cactus.pgm.bz2 | ./xvid_encraw -t 1 |
| 32 : | Isibaar | 3 | |
| 33 : | edgomez | 562 | This command decompress cactus.pgm.bz2 and pipe the pgm file to |
| 34 : | xvid_encraw that will compress it to mpeg4 format. No mp4 stream | ||
| 35 : | output is written to disc. | ||
| 36 : | Isibaar | 3 | |
| 37 : | edgomez | 562 | 2) ./xvid_encraw -t 1 -i cactus.pgm -m 1 |
| 38 : | Isibaar | 3 | |
| 39 : | edgomez | 562 | Compress cactus.pgm frames into mpeg4 stream, and then writes a m4v |
| 40 : | file per encoded frame. | ||
| 41 : | Isibaar | 3 | |
| 42 : | edgomez | 562 | 3) ./xvid_encraw -t 1 -i cactus.pgm -m 1 -o my_xvid_example.m4v |
| 43 : | Isibaar | 3 | |
| 44 : | edgomez | 562 | Same thing as above but saves all raw m4v data to a unique file. |
| 45 : | |||
| 46 : | 4) ./xvid_encraw -t 1 -i cactus.pgm -m 1 -mt 1 -o my_xvid_example.mp4u | ||
| 47 : | |||
| 48 : | Same as above but encapsulates the m4v stream into the mp4u file | ||
| 49 : | format. | ||
| 50 : | |||
| 51 : | ** xvid_decraw.c | ||
| 52 : | ---------------------------------------------------------------------- | ||
| 53 : | |||
| 54 : | This is a decoder example that is able to decode a m4v or mp4u | ||
| 55 : | stream. You can use it to decode what xvid_encraw encoded. | ||
| 56 : | |||
| 57 : | Type "xvid_decraw -help" to have all options' description. | ||
| 58 : | |||
| 59 : | Examples : | ||
| 60 : | |||
| 61 : | 1) ./xvid_decraw -w 352 -h 240 -t 1 -i stream.mp4u -d 1 | ||
| 62 : | |||
| 63 : | This command decodes a mp4u file (-t 1 option) from stream.mp4u and | ||
| 64 : | writes all decoded frames to single PGM files (framexxxxx.pgm). | ||
| 65 : | |||
| 66 : | 2) cat stream.m4v | ./xvid_decraw -w 352 -h 240 | ||
| 67 : | |||
| 68 : | This one reads a m4v file from standard input and outputs just | ||
| 69 : | decoding statistics. | ||
| 70 : | |||
| 71 : | NB :-w and -h parameters are mandatory as XviD lacks a "discover | ||
| 72 : | width and height" from m4v stream. This feature will be added at | ||
| 73 : | a later time, so for now we must use these options. | ||
| 74 : | |||
| 75 : | |||
| 76 : | * xvid_stat.c | ||
| 77 : | ---------------------------------------------------------------------- | ||
| 78 : | |||
| 79 : | This last example is a kind of xvid_dec/encraw merged program, it | ||
| 80 : | encodes PGM or YUV files and decode the resulting mp4 stream to | ||
| 81 : | measure both encoding and decoded times as well as PSNR. | ||
| 82 : | |||
| 83 : | Type "xvid_stat -help" to have all options' description. | ||
| 84 : | |||
| 85 : | Examples: | ||
| 86 : | |||
| 87 : | 1) ./xvid_stat < cactus.pgm | ||
| 88 : | |||
| 89 : | This calls xvid_stat with standard parameters for the 3 frames from | ||
| 90 : | the cactus file from examples directory. | ||
| 91 : | |||
| 92 : | Output should look similar to this: | ||
| 93 : | |||
| 94 : | Frame 0: intra 1, enctime = 4.7 ms length= 12470 bytes dectime = 4.2 ms PSNR 39.93 | ||
| 95 : | Frame 1: intra 0, enctime = 6.9 ms length= 1369 bytes dectime = 1.8 ms PSNR 40.40 | ||
| 96 : | Frame 2: intra 0, enctime = 6.6 ms length= 3354 bytes dectime = 2.3 ms PSNR 42.03 | ||
| 97 : | Avg. Q6 br 0900 (0.43 bpp) size 5731 (1146 kbps / 0.54 bpp) enc: 164.7 fps, dec: 362.0 fps | ||
| 98 : | PSNR P(2): 41.22 ( 40.40 , 42.03 ; 0.4698 ) I(1): 39.93 ( 39.93 , 39.93 ; 0.0000 ) | ||
| 99 : | |||
| 100 : | |||
| 101 : | The lines in detail: | ||
| 102 : | |||
| 103 : | For every input frame one line is printed containing the data: | ||
| 104 : | |||
| 105 : | Frame the frame number, starting with 0 | ||
| 106 : | |||
| 107 : | intra if the frame was encoded as I-frame (1) or P-frame (0), when | ||
| 108 : | B-frames are supported, they will get a value of 2 | ||
| 109 : | here. enctime time for encoding this frame, in milliseconds | ||
| 110 : | (1/1000th of a second) | ||
| 111 : | |||
| 112 : | length length of the MPEG-4 bitstream generated from this frame (in | ||
| 113 : | bytes) | ||
| 114 : | |||
| 115 : | dectime time for decoding | ||
| 116 : | |||
| 117 : | PSNR picture signal to noice ratio (a measurement of quality, | ||
| 118 : | higher is better) | ||
| 119 : | |||
| 120 : | Then in the end, two status lines are printed, these can be used, | ||
| 121 : | e.g. for automatic quality tests: | ||
| 122 : | |||
| 123 : | Avg. indicated that we are now talking about average values | ||
| 124 : | |||
| 125 : | Q6 quality parameter that was used (so here it was quality | ||
| 126 : | level 6) | ||
| 127 : | |||
| 128 : | br 0900 bitrate mode was used with a bitrate of 900kbps the other | ||
| 129 : | possibility is "q" instead of "br", see another example. | ||
| 130 : | |||
| 131 : | size 5731 average size of an encoded frame | ||
| 132 : | |||
| 133 : | 1146 kbps "real" bitrate that was achieved, it may differ from the | ||
| 134 : | bitrate given to the codec as a parameter, because this is | ||
| 135 : | real life | ||
| 136 : | |||
| 137 : | 0.54 bpp number of bit per pixel for the encoding, useful when | ||
| 138 : | comparing videos of different size | ||
| 139 : | |||
| 140 : | enc: 164.7 fps speed of encoding in frames per second | ||
| 141 : | |||
| 142 : | dec: 362.0 fps speed of decoding in frames per second | ||
| 143 : | |||
| 144 : | 2) ./xvid_stat -q 6 -b 900 -f 25 -i cactus.pgm | ||
| 145 : | |||
| 146 : | This does exactly the same as above, but parameters are provided | ||
| 147 : | instead of using default value. Output should be the same as in last | ||
| 148 : | example. Note that first and second parameter are 0, indicating | ||
| 149 : | that a PGM file should be read (which has a header that includes X | ||
| 150 : | and Y dimensions). | ||
| 151 : | |||
| 152 : | |||
| 153 : | 3) ./xvid_stat -t 1 -q 1 -quant 8 -i cactus.pgm | ||
| 154 : | |||
| 155 : | Output: | ||
| 156 : | |||
| 157 : | Frame 0: intra 1, enctime = 4.1 ms length= 8420 bytes dectime = 3.4 ms PSNR 36.36 | ||
| 158 : | Frame 1: intra 0, enctime = 3.0 ms length= 659 bytes dectime = 1.5 ms PSNR 36.36 | ||
| 159 : | Frame 2: intra 0, enctime = 2.7 ms length= 595 bytes dectime = 1.5 ms PSNR 36.43 | ||
| 160 : | Avg. Q1 q 0008 (0.00 bpp) size 3224 ( 644 kbps / 0.31 bpp)enc: 304.3 fps, dec: 467.1 fps | ||
| 161 : | PSNR P(2): 36.40 ( 36.36 , 36.43 ; 0.0210 ) I(1): 36.36 ( 36.36 , 36.36 ; 0.0000 ) | ||
| 162 : | |||
| 163 : | This time, quality 1 is used, so output values are a little | ||
| 164 : | different. Since the fourth parameter (here 8) is smaller than 32, | ||
| 165 : | it is not considered as a bitrate value, but as a fixed quantizer. | ||
| 166 : | So in the "Avg." line there is a : | ||
| 167 : | |||
| 168 : | q 0008 meaning "fixed quantizer mode" with quantizer 8. | ||
| 169 : | |||
| 170 : | 4) ./xvid_stat -w 176 -h 144 -q 5 -b 112 -i foreman.qcif | ||
| 171 : | |||
| 172 : | This switches xvid_stat to RAW instead of PGM mode. The input is | ||
| 173 : | expected to be images of dimensions 176*144 in raw YUV 4:2:0 | ||
| 174 : | format. (So every image is exactly 38016 = 176*144 + 88*72 + 88*72 | ||
| 175 : | bytes in size). Some reference streams are in this format. Note | ||
| 176 : | that you MUST give correct dimensions, because they cannot be | ||
| 177 : | detected from the YUV material. Apart from this, the example uses | ||
| 178 : | quality 5 and a bitrate of 112 kbps with video speed of 30 frames | ||
| 179 : | per second (this is not encoding or decoding speed, but the speed at | ||
| 180 : | which the video would be played. This value is only important for | ||
| 181 : | ratecontrol...) | ||
| 182 : | |||
| 183 : | |||
| 184 : | |||
| 185 : | ** MP4U Format | ||
| 186 : | ---------------------------------------------------------------------- | ||
| 187 : | |||
| 188 : | - Header : | ||
| 189 : | |||
| 190 : | +-----+-----+-----+-----+ | ||
| 191 : | | M | P | 4 | U | | ||
| 192 : | +-----+-----+-----+-----+ | ||
| 193 : | |1byte|1byte|1byte|1byte| | ||
| 194 : | +-----+-----+-----+-----+ | ||
| 195 : | |||
| 196 : | - Encoded frame | ||
| 197 : | |||
| 198 : | +------+----------------------- ... --+ | ||
| 199 : | | size | ... Frame data ... | | ||
| 200 : | +------+----------------------- ... --+ | ||
| 201 : | |4bytes| 'size' bytes | | ||
| 202 : | +------+----------------------- ... --+ | ||
| 203 : | |||
| 204 : | + size is written in big endian format | ||
| 205 : | + frame data is m4v raw data generated by XviD core. | ||
| 206 : | |||
| 207 : | - File format | ||
| 208 : | |||
| 209 : | Header + x*Encoded frame |
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