[FFmpeg-devel] [PATCH] avcodec/vp9_parser: parse size and colorspace values from frame headers

[James Almer]

Improves remuxing support when vp9 decoder is not compiled in.

Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavcodec/vp9_parser.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 97 insertions(+), 1 deletion(-)

diff --git a/libavcodec/vp9_parser.c b/libavcodec/vp9_parser.c
index 9531f34a32..b059477747 100644
--- a/libavcodec/vp9_parser.c
+++ b/libavcodec/vp9_parser.c
@@ -23,15 +23,69 @@
 
 #include "libavutil/intreadwrite.h"
 #include "libavcodec/get_bits.h"
+#include "libavcodec/internal.h"
 #include "parser.h"
 
+#define VP9_SYNCCODE 0x498342
+
+static int read_colorspace_details(AVCodecParserContext *ctx, AVCodecContext *avctx,
+                                   GetBitContext *gb)
+{
+    static const enum AVColorSpace colorspaces[8] = {
+        AVCOL_SPC_UNSPECIFIED, AVCOL_SPC_BT470BG, AVCOL_SPC_BT709, AVCOL_SPC_SMPTE170M,
+        AVCOL_SPC_SMPTE240M, AVCOL_SPC_BT2020_NCL, AVCOL_SPC_RESERVED, AVCOL_SPC_RGB,
+    };
+    int bits = avctx->profile <= 1 ? 0 : 1 + get_bits1(gb); // 0:8, 1:10, 2:12
+
+    avctx->colorspace = colorspaces[get_bits(gb, 3)];
+    if (avctx->colorspace == AVCOL_SPC_RGB) { // RGB = profile 1
+        static const enum AVPixelFormat pix_fmt_rgb[3] = {
+            AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP10, AV_PIX_FMT_GBRP12
+        };
+        if (avctx->profile & 1) {
+            if (get_bits1(gb)) // reserved bit
+                return AVERROR_INVALIDDATA;
+        } else
+            return AVERROR_INVALIDDATA;
+        avctx->color_range = AVCOL_RANGE_JPEG;
+        ctx->format = pix_fmt_rgb[bits];
+    } else {
+        static const enum AVPixelFormat pix_fmt_for_ss[3][2 /* v */][2 /* h */] = {
+            { { AV_PIX_FMT_YUV444P,   AV_PIX_FMT_YUV422P },
+              { AV_PIX_FMT_YUV440P,   AV_PIX_FMT_YUV420P } },
+            { { AV_PIX_FMT_YUV444P10, AV_PIX_FMT_YUV422P10 },
+              { AV_PIX_FMT_YUV440P10, AV_PIX_FMT_YUV420P10 } },
+            { { AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12 },
+              { AV_PIX_FMT_YUV440P12, AV_PIX_FMT_YUV420P12 } }
+        };
+        avctx->color_range = get_bits1(gb) ? AVCOL_RANGE_JPEG : AVCOL_RANGE_MPEG;
+        if (avctx->profile & 1) {
+            int ss_h, ss_v, format;
+
+            ss_h = get_bits1(gb);
+            ss_v = get_bits1(gb);
+            format = pix_fmt_for_ss[bits][ss_v][ss_h];
+            if (format == AV_PIX_FMT_YUV420P)
+                // YUV 4:2:0 not supported in profiles 1 and 3
+                return AVERROR_INVALIDDATA;
+            else if (get_bits1(gb)) // color details reserved bit
+                return AVERROR_INVALIDDATA;
+            ctx->format = format;
+        } else {
+            ctx->format = pix_fmt_for_ss[bits][1][1];
+        }
+    }
+
+    return 0;
+}
+
 static int parse(AVCodecParserContext *ctx,
                  AVCodecContext *avctx,
                  const uint8_t **out_data, int *out_size,
                  const uint8_t *data, int size)
 {
     GetBitContext gb;
-    int res, profile, keyframe;
+    int res, profile, keyframe, invisible, errorres;
 
     *out_data = data;
     *out_size = size;
@@ -42,21 +96,63 @@ static int parse(AVCodecParserContext *ctx,
     profile  = get_bits1(&gb);
     profile |= get_bits1(&gb) << 1;
     if (profile == 3) profile += get_bits1(&gb);
+    if (profile > 3)
+        return size;
 
     if (get_bits1(&gb)) {
         keyframe = 0;
+        skip_bits(&gb, 3);
     } else {
         keyframe  = !get_bits1(&gb);
     }
 
+    invisible = !get_bits1(&gb);
+    errorres  = get_bits1(&gb);
+
     if (!keyframe) {
+        int intraonly = invisible ? get_bits1(&gb) : 0;
+        if (!errorres)
+            skip_bits(&gb, 2);
+        if (intraonly) {
+            if (get_bits_long(&gb, 24) != VP9_SYNCCODE) // synccode
+                return size;
+            avctx->profile = profile;
+            if (profile >= 1) {
+                if ((read_colorspace_details(ctx, avctx, &gb)) < 0)
+                    return size;
+            } else {
+                ctx->format        = AV_PIX_FMT_YUV420P;
+                avctx->colorspace  = AVCOL_SPC_BT470BG;
+                avctx->color_range = AVCOL_RANGE_MPEG;
+            }
+            skip_bits(&gb, 8); // refreshrefmask
+            ctx->width  = get_bits(&gb, 16) + 1;
+            ctx->height = get_bits(&gb, 16) + 1;
+            if (get_bits1(&gb)) // display size
+                skip_bits(&gb, 32);
+        }
+
         ctx->pict_type = AV_PICTURE_TYPE_P;
         ctx->key_frame = 0;
     } else {
+        if (get_bits_long(&gb, 24) != VP9_SYNCCODE) // synccode
+            return size;
+        avctx->profile = profile;
+        if (read_colorspace_details(ctx, avctx, &gb) < 0)
+            return size;
+        ctx->width  = get_bits(&gb, 16) + 1;
+        ctx->height = get_bits(&gb, 16) + 1;
+        if (get_bits1(&gb)) // display size
+            skip_bits(&gb, 32);
+
         ctx->pict_type = AV_PICTURE_TYPE_I;
         ctx->key_frame = 1;
     }
 
+    if (ctx->width && (!avctx->width || !avctx->height ||
+                       !avctx->coded_width || !avctx->coded_height))
+        ff_set_dimensions(avctx, ctx->width, ctx->height);
+
     return size;
 }
 
-- 
2.15.0