Bitstream debug tool This is a debug tool used to detect bitstream error. On encoder side, it pushes each bit and probability into a queue before the bit is written into the Arithmetic coder. On decoder side, whenever a bit is read out from the Arithmetic coder, it pops up the reference bit and probability from the queue as well. If the two results do not match, this debug tool will report an error. This tool can be used to pin down the bitstream error precisely. By combining gdb's backtrace method, we can detect which module causes the bitstream error. Change-Id: I133a4371fafdd48c488f2ca47f9e395676c401f2
diff --git a/configure b/configure index 2b0722d..01b073f 100755 --- a/configure +++ b/configure
@@ -273,6 +273,7 @@ warped_motion entropy bidir_pred + bitstream_debug " CONFIG_LIST=" dependency_tracking
diff --git a/vp10/encoder/bitstream.c b/vp10/encoder/bitstream.c index 6c2cc6f..a5f7030 100644 --- a/vp10/encoder/bitstream.c +++ b/vp10/encoder/bitstream.c
@@ -18,6 +18,7 @@ #include "vpx_mem/vpx_mem.h" #include "vpx_ports/mem_ops.h" #include "vpx_ports/system_state.h" +#include "vpx_util/debug_util.h" #include "vp10/common/entropy.h" #include "vp10/common/entropymode.h" @@ -3583,6 +3584,10 @@ VP10_COMMON *const cm = &cpi->common; const int have_tiles = cm->tile_cols * cm->tile_rows > 1; +#if CONFIG_BITSTREAM_DEBUG + bitstream_queue_reset_write(); +#endif + // Write the uncompressed header write_uncompressed_header(cpi, &wb);
diff --git a/vp10/encoder/encoder.c b/vp10/encoder/encoder.c index 4b8dbc3..1767ad1 100644 --- a/vp10/encoder/encoder.c +++ b/vp10/encoder/encoder.c
@@ -59,6 +59,7 @@ #include "vpx_ports/system_state.h" #include "vpx_ports/vpx_timer.h" #include "vpx_scale/vpx_scale.h" +#include "vpx_util/debug_util.h" #define AM_SEGMENT_ID_INACTIVE 7 #define AM_SEGMENT_ID_ACTIVE 0 @@ -5419,6 +5420,12 @@ #endif // CONFIG_EXT_REFS int i; +#if CONFIG_BITSTREAM_DEBUG + assert(cpi->oxcf.max_threads == 0 && + "bitstream debug tool does not support multithreading"); + bitstream_queue_record_write(); +#endif + vpx_usec_timer_start(&cmptimer); vp10_set_high_precision_mv(cpi, ALTREF_HIGH_PRECISION_MV);
diff --git a/vpx_dsp/bitreader.h b/vpx_dsp/bitreader.h index 6ee2a58..1012454 100644 --- a/vpx_dsp/bitreader.h +++ b/vpx_dsp/bitreader.h
@@ -11,14 +11,21 @@ #ifndef VPX_DSP_BITREADER_H_ #define VPX_DSP_BITREADER_H_ -#include <stddef.h> #include <limits.h> +#include <stddef.h> #include "./vpx_config.h" + +#if CONFIG_BITSTREAM_DEBUG +#include <assert.h> +#include <stdio.h> +#endif // CONFIG_BITSTREAM_DEBUG + #include "vpx_ports/mem.h" #include "vpx/vp8dx.h" #include "vpx/vpx_integer.h" #include "vpx_dsp/prob.h" +#include "vpx_util/debug_util.h" #ifdef __cplusplus extern "C" { @@ -103,6 +110,22 @@ r->count = count; r->range = range; +#if CONFIG_BITSTREAM_DEBUG + { + int ref_bit, ref_prob; + const int queue_r = bitstream_queue_get_read(); + bitstream_queue_pop(&ref_bit, &ref_prob); + if (prob != ref_prob) { + fprintf(stderr, "prob error, prob %d ref_prob %d queue_r %d\n", prob, + ref_prob, queue_r); + assert(0); + } + if ((int)bit != ref_bit) { + fprintf(stderr, "bit error, bit %d ref_bit %d\n", bit, ref_bit); + assert(0); + } + } +#endif // CONFIG_BITSTREAM_DEBUG return bit; }
diff --git a/vpx_dsp/bitwriter.c b/vpx_dsp/bitwriter.c index 81e28b3..0abe351 100644 --- a/vpx_dsp/bitwriter.c +++ b/vpx_dsp/bitwriter.c
@@ -24,8 +24,16 @@ void vpx_stop_encode(vpx_writer *br) { int i; +#if CONFIG_BITSTREAM_DEBUG + bitstream_queue_set_skip_write(1); +#endif // CONFIG_BITSTREAM_DEBUG + for (i = 0; i < 32; i++) vpx_write_bit(br, 0); +#if CONFIG_BITSTREAM_DEBUG + bitstream_queue_set_skip_write(0); +#endif // CONFIG_BITSTREAM_DEBUG + // Ensure there's no ambigous collision with any index marker bytes if ((br->buffer[br->pos - 1] & 0xe0) == 0xc0) br->buffer[br->pos++] = 0; }
diff --git a/vpx_dsp/bitwriter.h b/vpx_dsp/bitwriter.h index 41040cf..5e952a8 100644 --- a/vpx_dsp/bitwriter.h +++ b/vpx_dsp/bitwriter.h
@@ -12,8 +12,8 @@ #define VPX_DSP_BITWRITER_H_ #include "vpx_ports/mem.h" - #include "vpx_dsp/prob.h" +#include "vpx_util/debug_util.h" #ifdef __cplusplus extern "C" { @@ -37,6 +37,10 @@ unsigned int lowvalue = br->lowvalue; register int shift; +#if CONFIG_BITSTREAM_DEBUG + bitstream_queue_push(bit, probability); +#endif // CONFIG_BITSTREAM_DEBUG + split = 1 + (((range - 1) * probability) >> 8); range = split;
diff --git a/vpx_util/debug_util.c b/vpx_util/debug_util.c new file mode 100644 index 0000000..6db1e0a --- /dev/null +++ b/vpx_util/debug_util.c
@@ -0,0 +1,59 @@ +/* + * Copyright (c) 2016 The WebM project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#include "vpx_util/debug_util.h" +#include <assert.h> +#include <stdio.h> +#if CONFIG_BITSTREAM_DEBUG +#define QUEUE_MAX_SIZE 2000000 +static int result_queue[QUEUE_MAX_SIZE]; +static int prob_queue[QUEUE_MAX_SIZE]; +static int queue_r = 0; +static int queue_w = 0; +static int queue_prev_w = -1; +static int skip_r = 0; +static int skip_w = 0; + +void bitstream_queue_set_skip_write(int skip) { skip_w = skip; } + +void bitstream_queue_set_skip_read(int skip) { skip_r = skip; } + +void bitstream_queue_record_write(void) { queue_prev_w = queue_w; } + +void bitstream_queue_reset_write(void) { queue_w = queue_prev_w; } + +int bitstream_queue_get_write(void) { return queue_w; } + +int bitstream_queue_get_read(void) { return queue_r; } + +void bitstream_queue_pop(int* result, int* prob) { + if (!skip_r) { + if (queue_w == queue_r) { + printf("buffer underflow queue_w %d queue_r %d\n", queue_w, queue_r); + assert(0); + } + *result = result_queue[queue_r]; + *prob = prob_queue[queue_r]; + queue_r = (queue_r + 1) % QUEUE_MAX_SIZE; + } +} + +void bitstream_queue_push(int result, int prob) { + if (!skip_w) { + result_queue[queue_w] = result; + prob_queue[queue_w] = prob; + queue_w = (queue_w + 1) % QUEUE_MAX_SIZE; + if (queue_w == queue_r) { + printf("buffer overflow queue_w %d queue_r %d\n", queue_w, queue_r); + assert(0); + } + } +} +#endif // CONFIG_BITSTREAM_DEBUG
diff --git a/vpx_util/debug_util.h b/vpx_util/debug_util.h new file mode 100644 index 0000000..0438be4 --- /dev/null +++ b/vpx_util/debug_util.h
@@ -0,0 +1,43 @@ +/* + * Copyright (c) 2016 The WebM project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#ifndef VPX_UTIL_DEBUG_UTIL_H_ +#define VPX_UTIL_DEBUG_UTIL_H_ + +#include "./vpx_config.h" + +#ifdef __cplusplus +extern "C" { +#endif + +#if CONFIG_BITSTREAM_DEBUG +/* This is a debug tool used to detect bitstream error. On encoder side, it + * pushes each bit and probability into a queue before the bit is written into + * the Arithmetic coder. On decoder side, whenever a bit is read out from the + * Arithmetic coder, it pops out the reference bit and probability from the + * queue as well. If the two results do not match, this debug tool will report + * an error. This tool can be used to pin down the bitstream error precisely. + * By combining gdb's backtrace method, we can detect which module causes the + * bitstream error. */ +int bitstream_queue_get_write(void); +int bitstream_queue_get_read(void); +void bitstream_queue_record_write(void); +void bitstream_queue_reset_write(void); +void bitstream_queue_pop(int *result, int *prob); +void bitstream_queue_push(int result, int prob); +void bitstream_queue_set_skip_write(int skip); +void bitstream_queue_set_skip_read(int skip); +#endif // CONFIG_BITSTREAM_DEBUG + +#ifdef __cplusplus +} // extern "C" +#endif + +#endif // VPX_UTIL_DEBUG_UTIL_H_
diff --git a/vpx_util/vpx_util.mk b/vpx_util/vpx_util.mk index c0ef8d3..480e61f 100644 --- a/vpx_util/vpx_util.mk +++ b/vpx_util/vpx_util.mk
@@ -11,4 +11,6 @@ UTIL_SRCS-yes += vpx_util.mk UTIL_SRCS-yes += vpx_thread.c UTIL_SRCS-yes += vpx_thread.h +UTIL_SRCS-yes += debug_util.c +UTIL_SRCS-yes += debug_util.h UTIL_SRCS-yes += endian_inl.h