[FFmpeg-devel] [PATCH] avcodec/vp9_parser: parse size and colorspace values from frame headers
Michael Niedermayer
michael at niedermayer.cc
Sat Jan 20 02:36:31 EET 2018
On Fri, Jan 19, 2018 at 09:33:46PM -0300, James Almer wrote:
> On 1/19/2018 8:56 PM, Michael Niedermayer wrote:
> > On Fri, Jan 19, 2018 at 12:51:21AM -0300, James Almer wrote:
> >> 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);
> >
> > This is the only ff_set_dimensions() in the codebase with non fixed parameters
> > that ignores the return value
> > is that intended ?
>
> Yes, since right after it the only line that remains in the entire
> function is the return.
>
> I can change it to "if (ff_set_dimensions() < 0) return size" if that's
> preferred, but it will be functionally the same since parsers can't
> return errors, so they always return the full frame size.
maybe write something like (void)ff_set_dimensions()
so its clear that you intended to ignore the return
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety -- Benjamin Franklin
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