3 @c man begin CODEC OPTIONS
5 libavcodec provides some generic global options, which can be set on
6 all the encoders and decoders. In addition each codec may support
7 so-called private options, which are specific for a given codec.
9 Sometimes, a global option may only affect a specific kind of codec,
10 and may be nonsensical or ignored by another, so you need to be aware
11 of the meaning of the specified options. Also some options are
12 meant only for decoding or encoding.
14 Options may be set by specifying -@var{option} @var{value} in the
15 FFmpeg tools, or by setting the value explicitly in the
16 @code{AVCodecContext} options or using the @file{libavutil/opt.h} API
19 The list of supported options follow:
22 @item b @var{integer} (@emph{encoding,audio,video})
23 Set bitrate in bits/s. Default value is 200K.
25 @item ab @var{integer} (@emph{encoding,audio})
26 Set audio bitrate (in bits/s). Default value is 128K.
28 @item bt @var{integer} (@emph{encoding,video})
29 Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate
30 tolerance specifies how far ratecontrol is willing to deviate from the
31 target average bitrate value. This is not related to min/max
32 bitrate. Lowering tolerance too much has an adverse effect on quality.
34 @item flags @var{flags} (@emph{decoding/encoding,audio,video,subtitles})
40 Use four motion vector by macroblock (mpeg4).
42 Use 1/4 pel motion compensation.
48 Use internal 2pass ratecontrol in first pass mode.
50 Use internal 2pass ratecontrol in second pass mode.
52 Only decode/encode grayscale.
56 Set error[?] variables during encoding.
64 Place global headers in extradata instead of every keyframe.
66 Only write platform-, build- and time-independent data. (except (I)DCT).
67 This ensures that file and data checksums are reproducible and match between
68 platforms. Its primary use is for regression testing.
70 Apply H263 advanced intra coding / mpeg4 ac prediction.
72 Deprecated, use mpegvideo private options instead.
74 Deprecated, use mpegvideo private options instead.
76 Apply interlaced motion estimation.
81 @item me_method @var{integer} (@emph{encoding,video})
82 Set motion estimation method.
87 zero motion estimation (fastest)
89 full motion estimation (slowest)
91 EPZS motion estimation (default)
93 esa motion estimation (alias for full)
95 tesa motion estimation
97 dia motion estimation (alias for epzs)
101 phods motion estimation
105 hex motion estimation
107 umh motion estimation
109 iter motion estimation
112 @item extradata_size @var{integer}
115 @item time_base @var{rational number}
118 It is the fundamental unit of time (in seconds) in terms of which
119 frame timestamps are represented. For fixed-fps content, timebase
120 should be @code{1 / frame_rate} and timestamp increments should be
123 @item g @var{integer} (@emph{encoding,video})
124 Set the group of picture (GOP) size. Default value is 12.
126 @item ar @var{integer} (@emph{decoding/encoding,audio})
127 Set audio sampling rate (in Hz).
129 @item ac @var{integer} (@emph{decoding/encoding,audio})
130 Set number of audio channels.
132 @item cutoff @var{integer} (@emph{encoding,audio})
133 Set cutoff bandwidth. (Supported only by selected encoders, see
134 their respective documentation sections.)
136 @item frame_size @var{integer} (@emph{encoding,audio})
137 Set audio frame size.
139 Each submitted frame except the last must contain exactly frame_size
140 samples per channel. May be 0 when the codec has
141 CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is not
142 restricted. It is set by some decoders to indicate constant frame
145 @item frame_number @var{integer}
146 Set the frame number.
148 @item delay @var{integer}
150 @item qcomp @var{float} (@emph{encoding,video})
151 Set video quantizer scale compression (VBR). It is used as a constant
152 in the ratecontrol equation. Recommended range for default rc_eq:
155 @item qblur @var{float} (@emph{encoding,video})
156 Set video quantizer scale blur (VBR).
158 @item qmin @var{integer} (@emph{encoding,video})
159 Set min video quantizer scale (VBR). Must be included between -1 and
160 69, default value is 2.
162 @item qmax @var{integer} (@emph{encoding,video})
163 Set max video quantizer scale (VBR). Must be included between -1 and
164 1024, default value is 31.
166 @item qdiff @var{integer} (@emph{encoding,video})
167 Set max difference between the quantizer scale (VBR).
169 @item bf @var{integer} (@emph{encoding,video})
170 Set max number of B frames between non-B-frames.
172 Must be an integer between -1 and 16. 0 means that B-frames are
173 disabled. If a value of -1 is used, it will choose an automatic value
174 depending on the encoder.
178 @item b_qfactor @var{float} (@emph{encoding,video})
179 Set qp factor between P and B frames.
181 @item rc_strategy @var{integer} (@emph{encoding,video})
182 Set ratecontrol method.
184 @item b_strategy @var{integer} (@emph{encoding,video})
185 Set strategy to choose between I/P/B-frames.
187 @item ps @var{integer} (@emph{encoding,video})
188 Set RTP payload size in bytes.
190 @item mv_bits @var{integer}
191 @item header_bits @var{integer}
192 @item i_tex_bits @var{integer}
193 @item p_tex_bits @var{integer}
194 @item i_count @var{integer}
195 @item p_count @var{integer}
196 @item skip_count @var{integer}
197 @item misc_bits @var{integer}
198 @item frame_bits @var{integer}
199 @item codec_tag @var{integer}
200 @item bug @var{flags} (@emph{decoding,video})
201 Workaround not auto detected encoder bugs.
208 some old lavc generated msmpeg4v3 files (no autodetection)
210 Xvid interlacing bug (autodetected if fourcc==XVIX)
212 (autodetected if fourcc==UMP4)
214 padding bug (autodetected)
218 illegal vlc bug (autodetected per fourcc)
222 old standard qpel (autodetected per fourcc/version)
225 @item direct_blocksize
226 direct-qpel-blocksize bug (autodetected per fourcc/version)
228 edge padding bug (autodetected per fourcc/version)
234 Workaround various bugs in microsoft broken decoders.
239 @item lelim @var{integer} (@emph{encoding,video})
240 Set single coefficient elimination threshold for luminance (negative
241 values also consider DC coefficient).
243 @item celim @var{integer} (@emph{encoding,video})
244 Set single coefficient elimination threshold for chrominance (negative
245 values also consider dc coefficient)
247 @item strict @var{integer} (@emph{decoding/encoding,audio,video})
248 Specify how strictly to follow the standards.
253 strictly conform to an older more strict version of the spec or reference software
255 strictly conform to all the things in the spec no matter what consequences
259 allow unofficial extensions
261 allow non standardized experimental things, experimental
262 (unfinished/work in progress/not well tested) decoders and encoders.
263 Note: experimental decoders can pose a security risk, do not use this for
264 decoding untrusted input.
267 @item b_qoffset @var{float} (@emph{encoding,video})
268 Set QP offset between P and B frames.
270 @item err_detect @var{flags} (@emph{decoding,audio,video})
271 Set error detection flags.
278 detect bitstream specification deviations
280 detect improper bitstream length
282 abort decoding on minor error detection
284 ignore decoding errors, and continue decoding.
285 This is useful if you want to analyze the content of a video and thus want
286 everything to be decoded no matter what. This option will not result in a video
287 that is pleasing to watch in case of errors.
289 consider things that violate the spec and have not been seen in the wild as errors
291 consider all spec non compliancies as errors
293 consider things that a sane encoder should not do as an error
296 @item has_b_frames @var{integer}
298 @item block_align @var{integer}
300 @item mpeg_quant @var{integer} (@emph{encoding,video})
301 Use MPEG quantizers instead of H.263.
303 @item qsquish @var{float} (@emph{encoding,video})
304 How to keep quantizer between qmin and qmax (0 = clip, 1 = use
305 differentiable function).
307 @item rc_qmod_amp @var{float} (@emph{encoding,video})
308 Set experimental quantizer modulation.
310 @item rc_qmod_freq @var{integer} (@emph{encoding,video})
311 Set experimental quantizer modulation.
313 @item rc_override_count @var{integer}
315 @item rc_eq @var{string} (@emph{encoding,video})
316 Set rate control equation. When computing the expression, besides the
317 standard functions defined in the section 'Expression Evaluation', the
318 following functions are available: bits2qp(bits), qp2bits(qp). Also
319 the following constants are available: iTex pTex tex mv fCode iCount
320 mcVar var isI isP isB avgQP qComp avgIITex avgPITex avgPPTex avgBPTex
323 @item maxrate @var{integer} (@emph{encoding,audio,video})
324 Set max bitrate tolerance (in bits/s). Requires bufsize to be set.
326 @item minrate @var{integer} (@emph{encoding,audio,video})
327 Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR
328 encode. It is of little use elsewise.
330 @item bufsize @var{integer} (@emph{encoding,audio,video})
331 Set ratecontrol buffer size (in bits).
333 @item rc_buf_aggressivity @var{float} (@emph{encoding,video})
336 @item i_qfactor @var{float} (@emph{encoding,video})
337 Set QP factor between P and I frames.
339 @item i_qoffset @var{float} (@emph{encoding,video})
340 Set QP offset between P and I frames.
342 @item rc_init_cplx @var{float} (@emph{encoding,video})
343 Set initial complexity for 1-pass encoding.
345 @item dct @var{integer} (@emph{encoding,video})
351 autoselect a good one (default)
361 floating point AAN DCT
364 @item lumi_mask @var{float} (@emph{encoding,video})
365 Compress bright areas stronger than medium ones.
367 @item tcplx_mask @var{float} (@emph{encoding,video})
368 Set temporal complexity masking.
370 @item scplx_mask @var{float} (@emph{encoding,video})
371 Set spatial complexity masking.
373 @item p_mask @var{float} (@emph{encoding,video})
376 @item dark_mask @var{float} (@emph{encoding,video})
377 Compress dark areas stronger than medium ones.
379 @item idct @var{integer} (@emph{decoding/encoding,video})
380 Select IDCT implementation.
393 Automatically pick a IDCT compatible with the simple one
416 floating point AAN IDCT
419 @item slice_count @var{integer}
421 @item ec @var{flags} (@emph{decoding,video})
422 Set error concealment strategy.
427 iterative motion vector (MV) search (slow)
429 use strong deblock filter for damaged MBs
431 favor predicting from the previous frame instead of the current
434 @item bits_per_coded_sample @var{integer}
436 @item pred @var{integer} (@emph{encoding,video})
437 Set prediction method.
449 @item aspect @var{rational number} (@emph{encoding,video})
450 Set sample aspect ratio.
452 @item sar @var{rational number} (@emph{encoding,video})
453 Set sample aspect ratio. Alias to @var{aspect}.
455 @item debug @var{flags} (@emph{decoding/encoding,audio,video,subtitles})
456 Print specific debug info.
469 per-block quantization parameter (QP)
475 display complexity metadata for the upcoming frame, GoP or for a given duration.
486 memory management control operations (H.264)
490 visualize quantization parameter (QP), lower QP are tinted greener
492 visualize block types
494 picture buffer allocations
498 skip motion compensation
501 @item cmp @var{integer} (@emph{encoding,video})
502 Set full pel me compare function.
507 sum of absolute differences, fast (default)
509 sum of squared errors
511 sum of absolute Hadamard transformed differences
513 sum of absolute DCT transformed differences
515 sum of squared quantization errors (avoid, low quality)
517 number of bits needed for the block
519 rate distortion optimal, slow
523 sum of absolute vertical differences
525 sum of squared vertical differences
527 noise preserving sum of squared differences
529 5/3 wavelet, only used in snow
531 9/7 wavelet, only used in snow
538 @item subcmp @var{integer} (@emph{encoding,video})
539 Set sub pel me compare function.
544 sum of absolute differences, fast (default)
546 sum of squared errors
548 sum of absolute Hadamard transformed differences
550 sum of absolute DCT transformed differences
552 sum of squared quantization errors (avoid, low quality)
554 number of bits needed for the block
556 rate distortion optimal, slow
560 sum of absolute vertical differences
562 sum of squared vertical differences
564 noise preserving sum of squared differences
566 5/3 wavelet, only used in snow
568 9/7 wavelet, only used in snow
575 @item mbcmp @var{integer} (@emph{encoding,video})
576 Set macroblock compare function.
581 sum of absolute differences, fast (default)
583 sum of squared errors
585 sum of absolute Hadamard transformed differences
587 sum of absolute DCT transformed differences
589 sum of squared quantization errors (avoid, low quality)
591 number of bits needed for the block
593 rate distortion optimal, slow
597 sum of absolute vertical differences
599 sum of squared vertical differences
601 noise preserving sum of squared differences
603 5/3 wavelet, only used in snow
605 9/7 wavelet, only used in snow
612 @item ildctcmp @var{integer} (@emph{encoding,video})
613 Set interlaced dct compare function.
618 sum of absolute differences, fast (default)
620 sum of squared errors
622 sum of absolute Hadamard transformed differences
624 sum of absolute DCT transformed differences
626 sum of squared quantization errors (avoid, low quality)
628 number of bits needed for the block
630 rate distortion optimal, slow
634 sum of absolute vertical differences
636 sum of squared vertical differences
638 noise preserving sum of squared differences
640 5/3 wavelet, only used in snow
642 9/7 wavelet, only used in snow
649 @item dia_size @var{integer} (@emph{encoding,video})
650 Set diamond type & size for motion estimation.
652 @item last_pred @var{integer} (@emph{encoding,video})
653 Set amount of motion predictors from the previous frame.
655 @item preme @var{integer} (@emph{encoding,video})
656 Set pre motion estimation.
658 @item precmp @var{integer} (@emph{encoding,video})
659 Set pre motion estimation compare function.
664 sum of absolute differences, fast (default)
666 sum of squared errors
668 sum of absolute Hadamard transformed differences
670 sum of absolute DCT transformed differences
672 sum of squared quantization errors (avoid, low quality)
674 number of bits needed for the block
676 rate distortion optimal, slow
680 sum of absolute vertical differences
682 sum of squared vertical differences
684 noise preserving sum of squared differences
686 5/3 wavelet, only used in snow
688 9/7 wavelet, only used in snow
695 @item pre_dia_size @var{integer} (@emph{encoding,video})
696 Set diamond type & size for motion estimation pre-pass.
698 @item subq @var{integer} (@emph{encoding,video})
699 Set sub pel motion estimation quality.
701 @item dtg_active_format @var{integer}
703 @item me_range @var{integer} (@emph{encoding,video})
704 Set limit motion vectors range (1023 for DivX player).
706 @item ibias @var{integer} (@emph{encoding,video})
707 Set intra quant bias.
709 @item pbias @var{integer} (@emph{encoding,video})
710 Set inter quant bias.
712 @item color_table_id @var{integer}
714 @item global_quality @var{integer} (@emph{encoding,audio,video})
716 @item coder @var{integer} (@emph{encoding,video})
721 variable length coder / huffman coder
732 @item context @var{integer} (@emph{encoding,video})
735 @item slice_flags @var{integer}
737 @item mbd @var{integer} (@emph{encoding,video})
738 Set macroblock decision algorithm (high quality mode).
747 use best rate distortion
750 @item stream_codec_tag @var{integer}
752 @item sc_threshold @var{integer} (@emph{encoding,video})
753 Set scene change threshold.
755 @item lmin @var{integer} (@emph{encoding,video})
756 Set min lagrange factor (VBR).
758 @item lmax @var{integer} (@emph{encoding,video})
759 Set max lagrange factor (VBR).
761 @item nr @var{integer} (@emph{encoding,video})
764 @item rc_init_occupancy @var{integer} (@emph{encoding,video})
765 Set number of bits which should be loaded into the rc buffer before
768 @item flags2 @var{flags} (@emph{decoding/encoding,audio,video})
773 Allow non spec compliant speedup tricks.
775 Deprecated, use mpegvideo private options instead.
777 Skip bitstream encoding.
779 Ignore cropping information from sps.
781 Place global headers at every keyframe instead of in extradata.
783 Frame data might be split into multiple chunks.
785 Show all frames before the first keyframe.
787 Deprecated, use mpegvideo private options instead.
789 Export motion vectors into frame side-data (see @code{AV_FRAME_DATA_MOTION_VECTORS})
790 for codecs that support it. See also @file{doc/examples/export_mvs.c}.
793 @item error @var{integer} (@emph{encoding,video})
795 @item qns @var{integer} (@emph{encoding,video})
796 Deprecated, use mpegvideo private options instead.
798 @item threads @var{integer} (@emph{decoding/encoding,video})
799 Set the number of threads to be used, in case the selected codec
800 implementation supports multi-threading.
805 automatically select the number of threads to set
808 Default value is @samp{auto}.
810 @item me_threshold @var{integer} (@emph{encoding,video})
811 Set motion estimation threshold.
813 @item mb_threshold @var{integer} (@emph{encoding,video})
814 Set macroblock threshold.
816 @item dc @var{integer} (@emph{encoding,video})
817 Set intra_dc_precision.
819 @item nssew @var{integer} (@emph{encoding,video})
822 @item skip_top @var{integer} (@emph{decoding,video})
823 Set number of macroblock rows at the top which are skipped.
825 @item skip_bottom @var{integer} (@emph{decoding,video})
826 Set number of macroblock rows at the bottom which are skipped.
828 @item profile @var{integer} (@emph{encoding,audio,video})
874 @item level @var{integer} (@emph{encoding,audio,video})
882 @item lowres @var{integer} (@emph{decoding,audio,video})
883 Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.
885 @item skip_threshold @var{integer} (@emph{encoding,video})
886 Set frame skip threshold.
888 @item skip_factor @var{integer} (@emph{encoding,video})
889 Set frame skip factor.
891 @item skip_exp @var{integer} (@emph{encoding,video})
892 Set frame skip exponent.
893 Negative values behave identical to the corresponding positive ones, except
894 that the score is normalized.
895 Positive values exist primarily for compatibility reasons and are not so useful.
897 @item skipcmp @var{integer} (@emph{encoding,video})
898 Set frame skip compare function.
903 sum of absolute differences, fast (default)
905 sum of squared errors
907 sum of absolute Hadamard transformed differences
909 sum of absolute DCT transformed differences
911 sum of squared quantization errors (avoid, low quality)
913 number of bits needed for the block
915 rate distortion optimal, slow
919 sum of absolute vertical differences
921 sum of squared vertical differences
923 noise preserving sum of squared differences
925 5/3 wavelet, only used in snow
927 9/7 wavelet, only used in snow
934 @item border_mask @var{float} (@emph{encoding,video})
935 Increase the quantizer for macroblocks close to borders.
937 @item mblmin @var{integer} (@emph{encoding,video})
938 Set min macroblock lagrange factor (VBR).
940 @item mblmax @var{integer} (@emph{encoding,video})
941 Set max macroblock lagrange factor (VBR).
943 @item mepc @var{integer} (@emph{encoding,video})
944 Set motion estimation bitrate penalty compensation (1.0 = 256).
946 @item skip_loop_filter @var{integer} (@emph{decoding,video})
947 @item skip_idct @var{integer} (@emph{decoding,video})
948 @item skip_frame @var{integer} (@emph{decoding,video})
950 Make decoder discard processing depending on the frame type selected
953 @option{skip_loop_filter} skips frame loop filtering, @option{skip_idct}
954 skips frame IDCT/dequantization, @option{skip_frame} skips decoding.
962 Discard useless frames like 0-sized frames.
965 Discard all non-reference frames.
968 Discard all bidirectional frames.
971 Discard all frames excepts keyframes.
977 Default value is @samp{default}.
979 @item bidir_refine @var{integer} (@emph{encoding,video})
980 Refine the two motion vectors used in bidirectional macroblocks.
982 @item brd_scale @var{integer} (@emph{encoding,video})
983 Downscale frames for dynamic B-frame decision.
985 @item keyint_min @var{integer} (@emph{encoding,video})
986 Set minimum interval between IDR-frames.
988 @item refs @var{integer} (@emph{encoding,video})
989 Set reference frames to consider for motion compensation.
991 @item chromaoffset @var{integer} (@emph{encoding,video})
992 Set chroma qp offset from luma.
994 @item trellis @var{integer} (@emph{encoding,audio,video})
995 Set rate-distortion optimal quantization.
997 @item sc_factor @var{integer} (@emph{encoding,video})
998 Set value multiplied by qscale for each frame and added to
1001 @item mv0_threshold @var{integer} (@emph{encoding,video})
1002 @item b_sensitivity @var{integer} (@emph{encoding,video})
1003 Adjust sensitivity of b_frame_strategy 1.
1005 @item compression_level @var{integer} (@emph{encoding,audio,video})
1006 @item min_prediction_order @var{integer} (@emph{encoding,audio})
1007 @item max_prediction_order @var{integer} (@emph{encoding,audio})
1008 @item timecode_frame_start @var{integer} (@emph{encoding,video})
1009 Set GOP timecode frame start number, in non drop frame format.
1011 @item request_channels @var{integer} (@emph{decoding,audio})
1012 Set desired number of audio channels.
1014 @item bits_per_raw_sample @var{integer}
1015 @item channel_layout @var{integer} (@emph{decoding/encoding,audio})
1020 @item request_channel_layout @var{integer} (@emph{decoding,audio})
1025 @item rc_max_vbv_use @var{float} (@emph{encoding,video})
1026 @item rc_min_vbv_use @var{float} (@emph{encoding,video})
1027 @item ticks_per_frame @var{integer} (@emph{decoding/encoding,audio,video})
1029 @item color_primaries @var{integer} (@emph{decoding/encoding,video})
1057 @item color_trc @var{integer} (@emph{decoding/encoding,video})
1102 @item colorspace @var{integer} (@emph{decoding/encoding,video})
1129 @item color_range @var{integer} (@emph{decoding/encoding,video})
1130 If used as input parameter, it serves as a hint to the decoder, which
1131 color_range the input has.
1142 @item chroma_sample_location @var{integer} (@emph{decoding/encoding,video})
1159 @item log_level_offset @var{integer}
1160 Set the log level offset.
1162 @item slices @var{integer} (@emph{encoding,video})
1163 Number of slices, used in parallelized encoding.
1165 @item thread_type @var{flags} (@emph{decoding/encoding,video})
1166 Select which multithreading methods to use.
1168 Use of @samp{frame} will increase decoding delay by one frame per
1169 thread, so clients which cannot provide future frames should not use
1175 Decode more than one part of a single frame at once.
1177 Multithreading using slices works only when the video was encoded with
1181 Decode more than one frame at once.
1184 Default value is @samp{slice+frame}.
1186 @item audio_service_type @var{integer} (@emph{encoding,audio})
1187 Set audio service type.
1211 @item request_sample_fmt @var{sample_fmt} (@emph{decoding,audio})
1212 Set sample format audio decoders should prefer. Default value is
1215 @item pkt_timebase @var{rational number}
1217 @item sub_charenc @var{encoding} (@emph{decoding,subtitles})
1218 Set the input subtitles character encoding.
1220 @item field_order @var{field_order} (@emph{video})
1221 Set/override the field order of the video.
1227 Interlaced video, top field coded and displayed first
1229 Interlaced video, bottom field coded and displayed first
1231 Interlaced video, top coded first, bottom displayed first
1233 Interlaced video, bottom coded first, top displayed first
1236 @item skip_alpha @var{bool} (@emph{decoding,video})
1237 Set to 1 to disable processing alpha (transparency). This works like the
1238 @samp{gray} flag in the @option{flags} option which skips chroma information
1239 instead of alpha. Default is 0.
1241 @item codec_whitelist @var{list} (@emph{input})
1242 "," separated list of allowed decoders. By default all are allowed.
1244 @item dump_separator @var{string} (@emph{input})
1245 Separator used to separate the fields printed on the command line about the
1247 For example to separate the fields with newlines and indention:
1249 ffprobe -dump_separator "
1250 " -i ~/videos/matrixbench_mpeg2.mpg
1253 @item max_pixels @var{integer} (@emph{decoding/encoding,video})
1254 Maximum number of pixels per image. This value can be used to avoid out of
1255 memory failures due to large images.
1257 @item apply_cropping @var{bool} (@emph{decoding,video})
1258 Enable cropping if cropping parameters are multiples of the required
1259 alignment for the left and top parameters. If the alignment is not met the
1260 cropping will be partially applied to maintain alignment.
1261 Default is 1 (enabled).
1262 Note: The required alignment depends on if @code{AV_CODEC_FLAG_UNALIGNED} is set and the
1263 CPU. @code{AV_CODEC_FLAG_UNALIGNED} cannot be changed from the command line. Also hardware
1264 decoders will not apply left/top Cropping.
1269 @c man end CODEC OPTIONS
1271 @ifclear config-writeonly
1272 @include decoders.texi
1274 @ifclear config-readonly
1275 @include encoders.texi