c++ - Broken output from libavcodec/swscale, depending on resolution -


i writing video conference software, have h.264 stream decoded libavcoded iyuv , rendered window vmr9 in windowless mode. use directshow graph so.

to avoid unnecessary conversion rgb , (see link), convert iyuv video yuy2 before passing vmr9, libswscale.

i noticed video resolution of 848x480, output video broken, investigated further , came resolutions video broken. exclude libswscale elaboration, added support iyuv+padding iyuv conversion, , worked, resolutions.

still, willing avoid slow iyuv, implemented support nv12 (with libswscale) , yv12 (manually, same iyuv). after doing tests on 2 different computers, came strange results.

resolution  yuy2    nv12    iyuv    yv12 pc 1 (my laptop)                 640x360     ok      broken  ok      broken 848x480     broken  broken  ok      broken 960x540     broken  broken  ok      broken 1024x576    ok      ok      ok      ok 1280x720    ok      ok      ok      broken 1920x1080   ok      broken  ok      broken  pc 2                 640x360     ok      ok      ok      ok 848x480     ok      broken  ok      broken 960x540     ok      ok      ok      ok 1024x576    ok      ok      ok      ok 1280x720    ok      broken  ok      ok 1920x1080   ok      ok      ok      ok

to exclude vmr9 fault, substituted evr, same results.

i know padding needed memory alignment, , size of padding depends on cpu used (libavcodec doc), may explain difference between 2 computers(first has intel i7-3820qm, second intel core 2 quad q6600). suppose has padding, because images corrupted in way. you can see blue t-shirt in lower part of image. can see blue t-shirt in lower part of image, , face in upper one.

to follow code conversion. nv12 , yuy2 conversions performed libswscale, while iyuv , yv12 manually.

int pixels = _outputframe->width * _outputframe->height; if (_outputformat == "yuy2") {     int stride = _outputframe->width * 2;     sws_scale(_convertctx, _outputframe->data, _outputframe->linesize, 0, _outputframe->height, &out, &stride); } else if (_outputformat == "nv12") {     int stride[] = { _outputframe->width, _outputframe->width };     uint8_t * dst[] = { out, out + pixels };     sws_scale(_convertctx, _outputframe->data, _outputframe->linesize, 0, _outputframe->height, dst, stride); } else if (_outputformat == "iyuv") { // clean ffmpeg padding     (int = 0; < _outputframe->height; i++) // copy y         memcpy(out + * _outputframe->width, _outputframe->data[0] + * _outputframe->linesize[0] , _outputframe->width);     (int = 0; < _outputframe->height / 2; i++) // copy u         memcpy(out + pixels + * _outputframe->width / 2, _outputframe->data[1] + * _outputframe->linesize[1] , _outputframe->width / 2);                 (int = 0; < _outputframe->height / 2; i++) // copy v         memcpy(out + pixels + pixels/4 + * _outputframe->width / 2, _outputframe->data[2] + * _outputframe->linesize[2] , _outputframe->width / 2); }  else if (_outputformat == "yv12") { // iyuv, u inverted v plane     (int = 0; < _outputframe->height; i++) // copy y         memcpy(out + * _outputframe->width, _outputframe->data[0] + * _outputframe->linesize[0], _outputframe->width);     (int = 0; < _outputframe->height / 2; i++) // copy v         memcpy(out + pixels + * _outputframe->width / 2, _outputframe->data[2] + * _outputframe->linesize[2], _outputframe->width / 2);     (int = 0; < _outputframe->height / 2; i++) // copy u         memcpy(out + pixels + pixels / 4 + * _outputframe->width / 2, _outputframe->data[1] + * _outputframe->linesize[1], _outputframe->width / 2); }

out output buffer. _outputframe libavcodec output avframe. _convertctx initialized follows.

if (_outputformat == "yuy2")     _convertctx = sws_getcontext(_width, _height, av_pix_fmt_yuv420p,                                  _width, _height, av_pix_fmt_yuyv422, sws_fast_bilinear, nullptr, nullptr, nullptr); else if (_outputformat == "nv12")     _convertctx = sws_getcontext(_width, _height, av_pix_fmt_yuv420p,                                  _width, _height, av_pix_fmt_nv12, sws_fast_bilinear, nullptr, nullptr, nullptr);

questions:

  1. are manual conversions correct?
  2. are assumptions correct?
  3. is previous 2 answers positive, problem? , especially...
  4. why presents resolutions , not others?
  5. what additional info can provide?


Comments

Post a Comment

Popular posts from this blog

commonjs - How to write a typescript definition file for a node module that exports a function? -

consider, toml node module can use: // toml.d.ts declare module toml { export function parse(value:string):any; } declare module "toml" { export = toml; } then: /// <reference path="../../../../../defs/toml/toml.d.ts"/> import toml = require('toml'); toml.parse(...); however, node module export single function, such 'glob' ( https://github.com/isaacs/node-glob ). the node usage of module be: var glob = require("glob") glob("*.js", {}, callback(err, files) { ... }); you'd naively expect this: // glob.d.ts declare function globs(paths:string, options:any, callback:{(err:any, files:string[]):void; ...but because typescripts 'import' semantics bit strange, seems can use 'import .. = require()' statement alias modules . trying call: /// <reference path="../../../../../defs/glob/glob.d.ts"/> import blog = require('glob'); results in: error ts2072: mod...
Read more

openid - Okta: Failed to get authorization code through API call -

i'm integrating okta own idp server using okta's api. i'm implementing authorization code flow following steps below: in own server, use /api/v1/authn endpoint sessiontoken. use sessiontoken obtain authorization calling endpoint: /oauth2/v1/authorize?client_id=" + clientid + "&sessiontoken=" + sessiontoken + "&response_type=code&response_mode=query&scope=openid&redirect_uri=" + redirecturl + "&state=evanyang&nonce=" it's supposed return response status code 302 , location header containing redirect url code value. however, keep getting response status code 200 , without location header, html body saying "you using unsupported browser." , "javascript disabled on browser." according api documentation: http://developer.okta.com/docs/api/resources/oidc.html#authentication-request , sessiontoken parameter sufficient this: an okta one-time sessiontoken. allows api-based ...
Read more

ios - Change Storyboard View using Seague -

i have following code checks connection server, , depending on want change views if no connection found. nsstring *connect = [nsstring stringwithcontentsofurl:[nsurl urlwithstring:@"http://myserver.com"] encoding:nsutf8stringencoding error:nil]; if (connect == null) { [self performseguewithidentifier:@"network_failure" sender:self]; } else { // other code here } my problem not change views. have added storyboard segue between 2 views identifier of network_failure . not have navigation controller or that, problem? thanks help! no not problem. first of all, in objectivec exists nil object oriented null . must use that. so: if(connect == nil) or better: if(!connect) so due fact nil not same of null , probably code does't enter in if scope . you have been able discover breakpoint. anyway: be sure set trigger segue (line) 2 view controller , , name network_failure (that not best name. should instead view1toview2 ) as, m...
Read more