video: make container vs. bitstream aspect ratio configurable

Utterly idiotic bullshit.

Fixes #2259.

DOCS/interface-changes.rst

@@ -20,6 +20,7 @@ Interface changes
 ::
 
  --- mpv 0.10.0 will be released ---
+    - add --video-aspect-method option
     - add --playlist-pos option
     - add --video-sync* options
       "display-sync-active" property

DOCS/man/options.rst

@@ -633,6 +633,23 @@ Video
     Ignore aspect ratio information from video file and assume the video has
     square pixels. See also ``--video-aspect``.
 
+``--video-aspect-method=<hybrid|bitstream|container>``
+    This sets the default video aspect determination method (if the aspect is
+    _not_ overridden by the user with ``--video-aspect`` or others).
+
+    :hybrid:    Prefer the container aspect ratio. If the bitstream aspect
+                switches mid-stream, switch to preferring the bitstream aspect.
+                This is the default behavior in mpv and mplayer2.
+    :container: Strictly prefer the container aspect ratio. This is apparently
+                the default behavior with VLC, at least with Matroska.
+    :bitstream: Strictly prefer the bitstream aspect ratio, unless the bitstream
+                aspect ratio is not set. This is apparently the default behavior
+                with XBMC/kodi, at least with Matroska.
+
+    Normally you should not set this. Try the ``container`` and ``bitstream``
+    choices if you encounter video that has the wrong aspect ratio in mpv,
+    but seems to be correct in other players.
+
 ``--video-unscaled``
     Disable scaling of the video. If the window is larger than the video,
     black bars are added. Otherwise, the video is cropped. The video still

common/av_common.c

@@ -59,7 +59,6 @@ void mp_copy_lav_codec_headers(AVCodecContext *avctx, AVCodecContext *st)
     avctx->width                    = st->width;
     avctx->height                   = st->height;
     avctx->pix_fmt                  = st->pix_fmt;
-    avctx->sample_aspect_ratio      = st->sample_aspect_ratio;
     avctx->chroma_sample_location   = st->chroma_sample_location;
     avctx->sample_rate              = st->sample_rate;
     avctx->channels                 = st->channels;

options/options.c

@@ -312,6 +312,8 @@ const m_option_t mp_opts[] = {
     //  0 means square pixels
     OPT_FLOATRANGE("video-aspect", movie_aspect, 0, -1.0, 10.0),
     OPT_FLOAT_STORE("no-video-aspect", movie_aspect, 0, 0.0),
+    OPT_CHOICE("video-aspect-method", aspect_method, 0,
+               ({"hybrid", 0}, {"bitstream", 1}, {"container", 2})),
 
     OPT_CHOICE("field-dominance", field_dominance, 0,
                ({"auto", -1}, {"top", 0}, {"bottom", 1})),

options/options.h

@@ -227,6 +227,7 @@ typedef struct MPOpts {
     struct m_obj_settings *af_settings, *af_defs;
     int deinterlace;
     float movie_aspect;
+    int aspect_method;
     int field_dominance;
     char **sub_name;
     char **sub_paths;

video/decode/dec_video.c

@@ -386,24 +386,45 @@ int video_reconfig_filters(struct dec_video *d_video,
     struct mp_image_params p = *params;
     struct sh_video *sh = d_video->header->video;
 
-    float decoder_aspect = p.d_w / (float)p.d_h;
+    // While mp_image_params normally always have to have d_w/d_h set, the
+    // decoder signals unknown bitstream aspect ratio with both set to 0.
+    float dec_aspect = p.d_w > 0 && p.d_h > 0 ? p.d_w / (float)p.d_h : 0;
     if (d_video->initial_decoder_aspect == 0)
-        d_video->initial_decoder_aspect = decoder_aspect;
+        d_video->initial_decoder_aspect = dec_aspect;
 
+    bool use_container = true;
+    switch (opts->aspect_method) {
+    case 0:
         // We normally prefer the container aspect, unless the decoder aspect
         // changes at least once.
-    if (d_video->initial_decoder_aspect == decoder_aspect) {
+        if (dec_aspect > 0 && d_video->initial_decoder_aspect != dec_aspect) {
-        if (sh->aspect > 0)
-            vf_set_dar(&p.d_w, &p.d_h, p.w, p.h, sh->aspect);
-    } else {
             MP_VERBOSE(d_video, "Using bitstream aspect ratio.\n");
             // Even if the aspect switches back, don't use container aspect again.
             d_video->initial_decoder_aspect = -1;
+            use_container = false;
+        }
+        break;
+    case 1:
+        use_container = false;
+        break;
+    }
+
+    if (use_container && sh->aspect > 0) {
+        MP_VERBOSE(d_video, "Using container aspect ratio.\n");
+        vf_set_dar(&p.d_w, &p.d_h, p.w, p.h, sh->aspect);
     }
 
     float force_aspect = opts->movie_aspect;
-    if (force_aspect >= 0.0)
+    if (force_aspect >= 0.0) {
+        MP_VERBOSE(d_video, "Forcing user-set aspect ratio.\n");
         vf_set_dar(&p.d_w, &p.d_h, p.w, p.h, force_aspect);
+    }
+
+    // Assume square pixels if no aspect ratio is set at all.
+    if (p.d_w <= 0 || p.d_h <= 0) {
+        p.d_w = p.w;
+        p.d_h = p.h;
+    }
 
     // Detect colorspace from resolution.
     mp_image_params_guess_csp(&p);

video/decode/vd_lavc.c

@@ -476,15 +476,12 @@ static void update_image_params(struct dec_video *vd, AVFrame *frame,
                    av_get_pix_fmt_name(pix_fmt));
     }
 
-    int d_w, d_h;
-    vf_set_dar(&d_w, &d_h, width, height, aspect);
-
     *out_params = (struct mp_image_params) {
         .imgfmt = ctx->best_csp,
         .w = width,
         .h = height,
-        .d_w = d_w,
+        .d_w = 0,
-        .d_h = d_h,
+        .d_h = 0,
         .colorspace = avcol_spc_to_mp_csp(ctx->avctx->colorspace),
         .colorlevels = avcol_range_to_mp_csp_levels(ctx->avctx->color_range),
         .primaries = avcol_pri_to_mp_csp_prim(ctx->avctx->color_primaries),
@@ -495,6 +492,9 @@ static void update_image_params(struct dec_video *vd, AVFrame *frame,
         .stereo_in = vd->header->video->stereo_mode,
     };
 
+    if (aspect > 0)
+        vf_set_dar(&out_params->d_w, &out_params->d_h, width, height, aspect);
+
     if (opts->video_rotate < 0) {
         out_params->rotate = 0;
     } else {