[FFmpeg-cvslog] r23889 - trunk/libavcodec/alsdec.c
thilo.borgmann
subversion
Tue Jun 29 18:56:29 CEST 2010
Author: thilo.borgmann
Date: Tue Jun 29 18:56:28 2010
New Revision: 23889
Log:
Add CRC check to the ALS decoder.
Modified:
trunk/libavcodec/alsdec.c
Modified: trunk/libavcodec/alsdec.c
==============================================================================
--- trunk/libavcodec/alsdec.c Tue Jun 29 16:48:45 2010 (r23888)
+++ trunk/libavcodec/alsdec.c Tue Jun 29 18:56:28 2010 (r23889)
@@ -35,6 +35,8 @@
#include "mpeg4audio.h"
#include "bytestream.h"
#include "bgmc.h"
+#include "dsputil.h"
+#include "libavutil/crc.h"
#include <stdint.h>
@@ -154,6 +156,7 @@ typedef struct {
uint32_t samples; ///< number of samples, 0xFFFFFFFF if unknown
int resolution; ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit
int floating; ///< 1 = IEEE 32-bit floating-point, 0 = integer
+ int msb_first; ///< 1 = original CRC calculated on big-endian system, 0 = little-endian
int frame_length; ///< frame length for each frame (last frame may differ)
int ra_distance; ///< distance between RA frames (in frames, 0...255)
enum RA_Flag ra_flag; ///< indicates where the size of ra units is stored
@@ -171,6 +174,7 @@ typedef struct {
int rlslms; ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off
int chan_config_info; ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.
int *chan_pos; ///< original channel positions
+ int crc_enabled; ///< enable Cyclic Redundancy Checksum
} ALSSpecificConfig;
@@ -188,6 +192,10 @@ typedef struct {
AVCodecContext *avctx;
ALSSpecificConfig sconf;
GetBitContext gb;
+ DSPContext dsp;
+ const AVCRC *crc_table;
+ uint32_t crc_org; ///< CRC value of the original input data
+ uint32_t crc; ///< CRC value calculated from decoded data
unsigned int cur_frame_length; ///< length of the current frame to decode
unsigned int frame_id; ///< the frame ID / number of the current frame
unsigned int js_switch; ///< if true, joint-stereo decoding is enforced
@@ -211,6 +219,7 @@ typedef struct {
int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
int32_t **raw_samples; ///< decoded raw samples for each channel
int32_t *raw_buffer; ///< contains all decoded raw samples including carryover samples
+ uint8_t *crc_buffer; ///< buffer of byte order corrected samples used for CRC check
} ALSDecContext;
@@ -268,7 +277,7 @@ static av_cold int read_specific_config(
{
GetBitContext gb;
uint64_t ht_size;
- int i, config_offset, crc_enabled;
+ int i, config_offset;
MPEG4AudioConfig m4ac;
ALSSpecificConfig *sconf = &ctx->sconf;
AVCodecContext *avctx = ctx->avctx;
@@ -297,7 +306,7 @@ static av_cold int read_specific_config(
skip_bits(&gb, 3); // skip file_type
sconf->resolution = get_bits(&gb, 3);
sconf->floating = get_bits1(&gb);
- skip_bits1(&gb); // skip msb_first
+ sconf->msb_first = get_bits1(&gb);
sconf->frame_length = get_bits(&gb, 16) + 1;
sconf->ra_distance = get_bits(&gb, 8);
sconf->ra_flag = get_bits(&gb, 2);
@@ -312,7 +321,7 @@ static av_cold int read_specific_config(
sconf->mc_coding = get_bits1(&gb);
sconf->chan_config = get_bits1(&gb);
sconf->chan_sort = get_bits1(&gb);
- crc_enabled = get_bits1(&gb);
+ sconf->crc_enabled = get_bits1(&gb);
sconf->rlslms = get_bits1(&gb);
skip_bits(&gb, 5); // skip 5 reserved bits
skip_bits1(&gb); // skip aux_data_enabled
@@ -375,12 +384,17 @@ static av_cold int read_specific_config(
skip_bits_long(&gb, ht_size);
- // skip the crc data
- if (crc_enabled) {
+ // initialize CRC calculation
+ if (sconf->crc_enabled) {
if (get_bits_left(&gb) < 32)
return -1;
- skip_bits_long(&gb, 32);
+ if (avctx->error_recognition >= FF_ER_CAREFUL) {
+ ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
+ ctx->crc = 0xFFFFFFFF;
+ ctx->crc_org = ~get_bits_long(&gb, 32);
+ } else
+ skip_bits_long(&gb, 32);
}
@@ -1437,6 +1451,59 @@ static int decode_frame(AVCodecContext *
INTERLEAVE_OUTPUT(32)
}
+ // update CRC
+ if (sconf->crc_enabled && avctx->error_recognition >= FF_ER_CAREFUL) {
+ int swap = HAVE_BIGENDIAN != sconf->msb_first;
+
+ if (ctx->avctx->bits_per_raw_sample == 24) {
+ int32_t *src = data;
+
+ for (sample = 0;
+ sample < ctx->cur_frame_length * avctx->channels;
+ sample++) {
+ int32_t v;
+
+ if (swap)
+ v = bswap_32(src[sample]);
+ else
+ v = src[sample];
+ if (!HAVE_BIGENDIAN)
+ v >>= 8;
+
+ ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);
+ }
+ } else {
+ uint8_t *crc_source;
+
+ if (swap) {
+ if (ctx->avctx->bits_per_raw_sample <= 16) {
+ int16_t *src = (int16_t*) data;
+ int16_t *dest = (int16_t*) ctx->crc_buffer;
+ for (sample = 0;
+ sample < ctx->cur_frame_length * avctx->channels;
+ sample++)
+ *dest++ = bswap_16(src[sample]);
+ } else {
+ ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer, data,
+ ctx->cur_frame_length * avctx->channels);
+ }
+ crc_source = ctx->crc_buffer;
+ } else {
+ crc_source = data;
+ }
+
+ ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source, size);
+ }
+
+
+ // check CRC sums if this is the last frame
+ if (ctx->cur_frame_length != sconf->frame_length &&
+ ctx->crc_org != ctx->crc) {
+ av_log(avctx, AV_LOG_ERROR, "CRC error.\n");
+ }
+ }
+
+
bytes_read = invalid_frame ? buffer_size :
(get_bits_count(&ctx->gb) + 7) >> 3;
@@ -1606,6 +1673,22 @@ static av_cold int decode_init(AVCodecCo
for (c = 1; c < avctx->channels; c++)
ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;
+ // allocate crc buffer
+ if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&
+ avctx->error_recognition >= FF_ER_CAREFUL) {
+ ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *
+ ctx->cur_frame_length *
+ avctx->channels *
+ (av_get_bits_per_sample_format(avctx->sample_fmt) >> 3));
+ if (!ctx->crc_buffer) {
+ av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
+ decode_end(avctx);
+ return AVERROR(ENOMEM);
+ }
+ }
+
+ dsputil_init(&ctx->dsp, avctx);
+
return 0;
}
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