qsvenc: Make sure the interlaced encoding works

Purpose: qsvenc: make sure that interlaced encoding works.  Also,
reduce the vertical alignment constraint when possible to reduce
memory usage.

Note: Most of this code used to be present in ffmpeg and was
eliminated in revision 1f26a23 on Oct. 31, 2016 (qsv: Merge libav
implementation, at
https://github.com/FFmpeg/FFmpeg/commit/1f26a231bb065276cd80ce02957c759f3197
edfa#diff-7d84a34d58597bb7aa4b8239dca1f9f8).  Already applied to
libav.

Reviewed-by: Luca Barbato <lu_zero@gentoo.org>
(cherry picked from commit 8fd8f91e47)
Signed-off-by: Mark Thompson <sw@jkqxz.net>
Signed-off-by: Aaron Levinson <alevinsn@aracnet.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/qsvenc.c

@@ -358,8 +358,6 @@ static int init_video_param(AVCodecContext *avctx, QSVEncContext *q)
         return AVERROR_BUG;
     q->param.mfx.CodecId = ret;
 
-    q->width_align = avctx->codec_id == AV_CODEC_ID_HEVC ? 32 : 16;
-
     if (avctx->level > 0)
         q->param.mfx.CodecLevel = avctx->level;
 
@@ -381,20 +379,39 @@ static int init_video_param(AVCodecContext *avctx, QSVEncContext *q)
 
     ff_qsv_map_pixfmt(sw_format, &q->param.mfx.FrameInfo.FourCC);
 
-    q->param.mfx.FrameInfo.Width          = FFALIGN(avctx->width, q->width_align);
-    q->param.mfx.FrameInfo.Height         = FFALIGN(avctx->height, 32);
     q->param.mfx.FrameInfo.CropX          = 0;
     q->param.mfx.FrameInfo.CropY          = 0;
     q->param.mfx.FrameInfo.CropW          = avctx->width;
     q->param.mfx.FrameInfo.CropH          = avctx->height;
     q->param.mfx.FrameInfo.AspectRatioW   = avctx->sample_aspect_ratio.num;
     q->param.mfx.FrameInfo.AspectRatioH   = avctx->sample_aspect_ratio.den;
-    q->param.mfx.FrameInfo.PicStruct      = MFX_PICSTRUCT_PROGRESSIVE;
     q->param.mfx.FrameInfo.ChromaFormat   = MFX_CHROMAFORMAT_YUV420;
     q->param.mfx.FrameInfo.BitDepthLuma   = desc->comp[0].depth;
     q->param.mfx.FrameInfo.BitDepthChroma = desc->comp[0].depth;
     q->param.mfx.FrameInfo.Shift          = desc->comp[0].depth > 8;
 
+    // TODO:  detect version of MFX--if the minor version is greater than
+    // or equal to 19, then can use the same alignment settings as H.264
+    // for HEVC
+    q->width_align = avctx->codec_id == AV_CODEC_ID_HEVC ? 32 : 16;
+    q->param.mfx.FrameInfo.Width = FFALIGN(avctx->width, q->width_align);
+
+    if (avctx->flags & AV_CODEC_FLAG_INTERLACED_DCT) {
+        // it is important that PicStruct be setup correctly from the
+        // start--otherwise, encoding doesn't work and results in a bunch
+        // of incompatible video parameter errors
+        q->param.mfx.FrameInfo.PicStruct = MFX_PICSTRUCT_FIELD_TFF;
+        // height alignment always must be 32 for interlaced video
+        q->height_align = 32;
+    } else {
+        q->param.mfx.FrameInfo.PicStruct = MFX_PICSTRUCT_PROGRESSIVE;
+        // for progressive video, the height should be aligned to 16 for
+        // H.264.  For HEVC, depending on the version of MFX, it should be
+        // either 32 or 16.  The lower number is better if possible.
+        q->height_align = avctx->codec_id == AV_CODEC_ID_HEVC ? 32 : 16;
+    }
+    q->param.mfx.FrameInfo.Height = FFALIGN(avctx->height, q->height_align);
+
     if (avctx->hw_frames_ctx) {
         AVHWFramesContext *frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
         AVQSVFramesContext *frames_hwctx = frames_ctx->hwctx;
@@ -898,7 +915,7 @@ static int submit_frame(QSVEncContext *q, const AVFrame *frame,
     } else {
         /* make a copy if the input is not padded as libmfx requires */
         if (frame->height & 31 || frame->linesize[0] & (q->width_align - 1)) {
-            qf->frame->height = FFALIGN(frame->height, 32);
+            qf->frame->height = FFALIGN(frame->height, q->height_align);
             qf->frame->width  = FFALIGN(frame->width, q->width_align);
 
             ret = ff_get_buffer(q->avctx, qf->frame, AV_GET_BUFFER_FLAG_REF);

libavcodec/qsvenc.h

@@ -84,6 +84,7 @@ typedef struct QSVEncContext {
 
     int packet_size;
     int width_align;
+    int height_align;
 
     mfxVideoParam param;
     mfxFrameAllocRequest req;