avcodec/cbs_vp8: Add support for VP8 codec bitstream

This commit adds support for VP8 bitstream read methods to the cbs
codec. This enables the trace_headers bitstream filter to support VP8,
in addition to AV1, H.264, H.265, and VP9. This can be useful for
debugging VP8 stream issues.

The CBS VP8 implements a simple VP8 boolean decoder using GetBitContext
to read the bitstream.

Only the read methods `read_unit` and `split_fragment` are implemented.
The write methods `write_unit` and `assemble_fragment` return the error
code AVERROR_PATCHWELCOME. This is because CBS VP8 write is unlikely to
be used by any applications at the moment. The write methods can be
added later if there is a real need for them.

TESTS: ffmpeg -i fate-suite/vp8/frame_size_change.webm -vcodec copy
-bsf:v trace_headers -f null -

Signed-off-by: Jianhui Dai <jianhui.j.dai@intel.com>
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/libavcodec/cbs_vp8.h b/libavcodec/cbs_vp8.h
new file mode 100644
index 0000000000..9c09e21a1c
--- /dev/null
+++ b/libavcodec/cbs_vp8.h
@@ -0,0 +1,133 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_CBS_VP8_H
+#define AVCODEC_CBS_VP8_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "cbs.h"
+
+enum {
+    VP8_START_CODE_0 = 0x9D,
+    VP8_START_CODE_1 = 0x01,
+    VP8_START_CODE_2 = 0x2A,
+};
+
+enum {
+    VP8_KEY_FRAME = 0,
+    VP8_NON_KEY_FRAME = 1,
+};
+
+typedef struct VP8RawFrameHeader {
+    // frame tag
+    uint8_t frame_type;
+    uint8_t profile;
+    uint8_t show_frame;
+    uint32_t first_partition_length_in_bytes;
+
+    uint16_t width;
+    uint8_t horizontal_scale;
+    uint16_t height;
+    uint8_t vertical_scale;
+
+    // frame header
+    uint8_t color_space;
+    uint8_t clamping_type;
+
+    // segmentation
+    uint8_t segmentation_enable;
+    uint8_t update_segment_map;
+    uint8_t update_segment_feature_data;
+    uint8_t segment_feature_mode;
+    uint8_t segment_qp_update[4];
+    int8_t segment_qp[4];
+    uint8_t segment_loop_filter_level_update[4];
+    int8_t segment_loop_filter_level[4];
+    uint8_t segment_probs_update[3];
+    uint8_t segment_probs[3];
+
+    // loop filter
+    uint8_t loop_filter_type;
+    uint8_t loop_filter_level;
+    uint8_t loop_filter_sharpness;
+    uint8_t mode_ref_lf_delta_enable;
+    uint8_t mode_ref_lf_delta_update;
+    uint8_t ref_lf_deltas_update[4];
+    int8_t ref_lf_deltas[4];
+    uint8_t mode_lf_deltas_update[4];
+    int8_t mode_lf_deltas[4];
+
+    uint8_t log2_token_partitions;
+
+    // qp
+    uint8_t base_qindex;
+    uint8_t y1dc_delta_q_present;
+    int8_t y1dc_delta_q;
+    uint8_t y2dc_delta_q_present;
+    int8_t y2dc_delta_q;
+    uint8_t y2ac_delta_q_present;
+    int8_t y2ac_delta_q;
+    uint8_t uvdc_delta_q_present;
+    int8_t uvdc_delta_q;
+    uint8_t uvac_delta_q_present;
+    int8_t uvac_delta_q;
+
+    // ref
+    uint8_t refresh_golden_frame;
+    uint8_t refresh_alternate_frame;
+    uint8_t copy_buffer_to_golden;
+    uint8_t copy_buffer_to_alternate;
+    uint8_t ref_frame_sign_bias_golden;
+    uint8_t ref_frame_sign_bias_alternate;
+    uint8_t refresh_last_frame;
+
+    uint8_t refresh_entropy_probs;
+
+    // token probs
+    uint8_t coeff_prob_update[4][8][3][11];
+    uint8_t coeff_prob[4][8][3][11];
+
+    uint8_t mb_no_skip_coeff;
+    uint8_t prob_skip_false;
+
+    uint8_t prob_intra;
+    uint8_t prob_last;
+    uint8_t prob_golden;
+
+    uint8_t intra_16x16_prob_update;
+    uint8_t intra_16x16_prob[4];
+
+    uint8_t intra_chrome_prob_update;
+    uint8_t intra_chrome_prob[3];
+
+    // mv probs
+    uint8_t mv_prob_update[2][19];
+    uint8_t mv_prob[2][19];
+} VP8RawFrameHeader;
+
+typedef struct VP8RawFrame {
+    VP8RawFrameHeader header;
+
+    uint8_t *data;
+    AVBufferRef *data_ref;
+    size_t data_size;
+} VP8RawFrame;
+
+#endif /* AVCODEC_CBS_VP8_H */