[FFmpeg-devel] [PATCH] avfilter/vf_stereo3d: implement auto detection by using frame side data

[Paul B Mahol]

On 11/30/17, wm4 <nfxjfg at googlemail.com> wrote:
> On Wed, 29 Nov 2017 23:15:44 +0100
> Paul B Mahol <onemda at gmail.com> wrote:
>
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> ---
>>  doc/filters.texi          |  4 ++++
>>  libavfilter/vf_stereo3d.c | 35 ++++++++++++++++++++++++++++++++---
>>  2 files changed, 36 insertions(+), 3 deletions(-)
>>
>> diff --git a/doc/filters.texi b/doc/filters.texi
>> index 4a4efc70c8..e8da5e21a6 100644
>> --- a/doc/filters.texi
>> +++ b/doc/filters.texi
>> @@ -14057,6 +14057,10 @@ Set stereoscopic image format of input.
>>
>>  Available values for input image formats are:
>>  @table @samp
>> + at item auto
>> +set input format using frame side data
>> +If such data is not available filter will return unchanged input.
>> +
>>  @item sbsl
>>  side by side parallel (left eye left, right eye right)
>>
>> diff --git a/libavfilter/vf_stereo3d.c b/libavfilter/vf_stereo3d.c
>> index 8b22f880ca..a51fbeb75d 100644
>> --- a/libavfilter/vf_stereo3d.c
>> +++ b/libavfilter/vf_stereo3d.c
>> @@ -25,6 +25,7 @@
>>  #include "libavutil/opt.h"
>>  #include "libavutil/parseutils.h"
>>  #include "libavutil/pixdesc.h"
>> +#include "libavutil/stereo3d.h"
>>  #include "avfilter.h"
>>  #include "drawutils.h"
>>  #include "formats.h"
>> @@ -47,8 +48,8 @@ enum StereoCode {
>>      ANAGLYPH_YB_DUBOIS, // anaglyph yellow/blue dubois
>>      ANAGLYPH_RB_GRAY,   // anaglyph red/blue gray
>>      ANAGLYPH_RG_GRAY,   // anaglyph red/green gray
>> -    MONO_L,             // mono output for debugging (left eye only)
>> -    MONO_R,             // mono output for debugging (right eye only)
>> +    MONO_L,             // mono output (left eye only)
>> +    MONO_R,             // mono output (right eye only)
>>      INTERLEAVE_ROWS_LR, // row-interleave (left eye has top row)
>>      INTERLEAVE_ROWS_RL, // row-interleave (right eye has top row)
>>      SIDE_BY_SIDE_LR,    // side by side parallel (left eye left, right
>> eye right)
>> @@ -66,7 +67,8 @@ enum StereoCode {
>>      INTERLEAVE_COLS_LR, // column-interleave (left eye first, right eye
>> second)
>>      INTERLEAVE_COLS_RL, // column-interleave (right eye first, left eye
>> second)
>>      HDMI,               // HDMI frame pack (left eye first, right eye
>> second)
>> -    STEREO_CODE_COUNT   // TODO: needs autodetection
>> +    AUTO,               // guess input format using frame's metadata.
>> +    STEREO_CODE_COUNT
>>  };
>>
>>  typedef struct StereoComponent {
>> @@ -173,6 +175,7 @@ static const AVOption stereo3d_options[] = {
>>      { "irr",   "interleave rows right first",         0,
>> AV_OPT_TYPE_CONST, {.i64=INTERLEAVE_ROWS_RL}, 0, 0, FLAGS, "in" },
>>      { "icl",   "interleave columns left first",       0,
>> AV_OPT_TYPE_CONST, {.i64=INTERLEAVE_COLS_LR}, 0, 0, FLAGS, "in" },
>>      { "icr",   "interleave columns right first",      0,
>> AV_OPT_TYPE_CONST, {.i64=INTERLEAVE_COLS_RL}, 0, 0, FLAGS, "in" },
>> +    { "auto",  "guess using frame metadata",          0,
>> AV_OPT_TYPE_CONST, {.i64=AUTO},               0, 0, FLAGS, "in" },
>>      { "out",   "set output format", OFFSET(out.format),  AV_OPT_TYPE_INT,
>>   {.i64=ANAGLYPH_RC_DUBOIS}, 0, STEREO_CODE_COUNT-1, FLAGS, "out"},
>>      { "ab2l",  "above below half height left first",  0,
>> AV_OPT_TYPE_CONST, {.i64=ABOVE_BELOW_2_LR},   0, 0, FLAGS, "out" },
>>      { "ab2r",  "above below half height right first", 0,
>> AV_OPT_TYPE_CONST, {.i64=ABOVE_BELOW_2_RL},   0, 0, FLAGS, "out" },
>> @@ -366,6 +369,9 @@ static int config_output(AVFilterLink *outlink)
>>      int ret;
>>      s->aspect = inlink->sample_aspect_ratio;
>>
>> +    if (s->in.format == AUTO || (s->in.format == s->out.format))
>> +        return 0;
>> +
>>      switch (s->in.format) {
>>      case INTERLEAVE_COLS_LR:
>>      case INTERLEAVE_COLS_RL:
>> @@ -670,6 +676,29 @@ static int filter_frame(AVFilterLink *inlink, AVFrame
>> *inpicref)
>>      int out_off_left[4], out_off_right[4];
>>      int i, ret;
>>
>> +    if (s->in.format == AUTO) {
>> +        AVFrameSideData *sd = av_frame_get_side_data(inpicref,
>> AV_FRAME_DATA_STEREO3D);
>> +
>> +        if (sd) {
>> +            AVStereo3D *s3d = (AVStereo3D *)sd->data;
>> +
>> +            switch (s3d->type) {
>> +            case AV_STEREO3D_SIDEBYSIDE:          s->in.format =
>> SIDE_BY_SIDE_LR;    break;
>> +            case AV_STEREO3D_SIDEBYSIDE_QUINCUNX: s->in.format =
>> SIDE_BY_SIDE_LR;    break;
>> +            case AV_STEREO3D_TOPBOTTOM:           s->in.format =
>> ABOVE_BELOW_LR;     break;
>> +            case AV_STEREO3D_CHECKERBOARD:        s->in.format =
>> CHECKERBOARD_LR;    break;
>> +            case AV_STEREO3D_FRAMESEQUENCE:       s->in.format =
>> ALTERNATING_LR;     break;
>> +            case AV_STEREO3D_LINES:               s->in.format =
>> INTERLEAVE_ROWS_LR; break;
>> +            case AV_STEREO3D_COLUMNS:             s->in.format =
>> INTERLEAVE_COLS_LR; break;
>> +            default:                              s->in.format =
>> s->out.format = MONO_L;
>> +            };
>> +        } else {
>> +            s->in.format = s->out.format = MONO_L;
>> +        }
>> +        if ((ret = config_output(outlink)) < 0)
>> +            return ret;
>
> Attempting midstream parameter changes is an API violation.

No it is not.