Chiebot-Mirror
/
FFmpeg
mirror of https://github.com/FFmpeg/FFmpeg.git
8
0
Fork 0
Code Issues Projects Releases Wiki Activity

avcodec/wmaprodec: Make decoders init-threadsafe

Browse Source 
In this case this actually fixes a potential data race: The static VLC
tables were reinitialized every time an AVCodecContext has been
initialized; while the mutex in avcodec_open2() ensured that the VLCs
could not be initialized concurrently by multiple threads, nothing
guaranteed that these VLCs are not read concurrently (when decoding a
packet with an already initialized AVCodecContext) while another thread
initializes them. This is undefined behaviour despite the values being
written coinciding with the earlier values.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
pull/362/head
Andreas Rheinhardt 4 years ago
parent a1b0148366
commit 3c3712ee2b
1 changed files with 39 additions and 36 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Unified View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 75
      libavcodec/wmaprodec.c

75
libavcodec/wmaprodec.c
Unescape View File

@ -93,6 +93,7 @@
#include "libavutil/intfloat.h" #include "libavutil/intfloat.h"
#include "libavutil/intreadwrite.h" #include "libavutil/intreadwrite.h"
#include "libavutil/mem_internal.h" #include "libavutil/mem_internal.h"
#include "libavutil/thread.h"
#include "avcodec.h" #include "avcodec.h"
#include "internal.h" #include "internal.h"
@ -309,6 +310,38 @@ static av_cold int get_rate(AVCodecContext *avctx)
return avctx->sample_rate; return avctx->sample_rate;
} }
static av_cold void decode_init_static(void)
{
INIT_VLC_STATIC(&sf_vlc, SCALEVLCBITS, HUFF_SCALE_SIZE,
scale_huffbits, 1, 1,
scale_huffcodes, 2, 2, 616);
INIT_VLC_STATIC(&sf_rl_vlc, VLCBITS, HUFF_SCALE_RL_SIZE,
scale_rl_huffbits, 1, 1,
scale_rl_huffcodes, 4, 4, 1406);
INIT_VLC_STATIC(&coef_vlc[0], VLCBITS, HUFF_COEF0_SIZE,
coef0_huffbits, 1, 1,
coef0_huffcodes, 4, 4, 2108);
INIT_VLC_STATIC(&coef_vlc[1], VLCBITS, HUFF_COEF1_SIZE,
coef1_huffbits, 1, 1,
coef1_huffcodes, 4, 4, 3912);
INIT_VLC_STATIC(&vec4_vlc, VLCBITS, HUFF_VEC4_SIZE,
vec4_huffbits, 1, 1,
vec4_huffcodes, 2, 2, 604);
INIT_VLC_STATIC(&vec2_vlc, VLCBITS, HUFF_VEC2_SIZE,
vec2_huffbits, 1, 1,
vec2_huffcodes, 2, 2, 562);
INIT_VLC_STATIC(&vec1_vlc, VLCBITS, HUFF_VEC1_SIZE,
vec1_huffbits, 1, 1,
vec1_huffcodes, 2, 2, 562);
/** calculate sine values for the decorrelation matrix */
for (int i = 0; i < 33; i++)
sin64[i] = sin(i * M_PI / 64.0);
for (int i = WMAPRO_BLOCK_MIN_BITS; i <= WMAPRO_BLOCK_MAX_BITS; i++)
ff_init_ff_sine_windows(i);
}
/** /**
*@brief Initialize the decoder. *@brief Initialize the decoder.
*@param avctx codec context *@param avctx codec context
@ -316,6 +349,7 @@ static av_cold int get_rate(AVCodecContext *avctx)
*/ */
static av_cold int decode_init(WMAProDecodeCtx *s, AVCodecContext *avctx, int num_stream) static av_cold int decode_init(WMAProDecodeCtx *s, AVCodecContext *avctx, int num_stream)
{ {
static AVOnce init_static_once = AV_ONCE_INIT;
uint8_t *edata_ptr = avctx->extradata; uint8_t *edata_ptr = avctx->extradata;
unsigned int channel_mask; unsigned int channel_mask;
int i, bits, ret; int i, bits, ret;
@ -460,34 +494,6 @@ static av_cold int decode_init(WMAProDecodeCtx *s, AVCodecContext *avctx, int nu
} }
} }
INIT_VLC_STATIC(&sf_vlc, SCALEVLCBITS, HUFF_SCALE_SIZE,
scale_huffbits, 1, 1,
scale_huffcodes, 2, 2, 616);
INIT_VLC_STATIC(&sf_rl_vlc, VLCBITS, HUFF_SCALE_RL_SIZE,
scale_rl_huffbits, 1, 1,
scale_rl_huffcodes, 4, 4, 1406);
INIT_VLC_STATIC(&coef_vlc[0], VLCBITS, HUFF_COEF0_SIZE,
coef0_huffbits, 1, 1,
coef0_huffcodes, 4, 4, 2108);
INIT_VLC_STATIC(&coef_vlc[1], VLCBITS, HUFF_COEF1_SIZE,
coef1_huffbits, 1, 1,
coef1_huffcodes, 4, 4, 3912);
INIT_VLC_STATIC(&vec4_vlc, VLCBITS, HUFF_VEC4_SIZE,
vec4_huffbits, 1, 1,
vec4_huffcodes, 2, 2, 604);
INIT_VLC_STATIC(&vec2_vlc, VLCBITS, HUFF_VEC2_SIZE,
vec2_huffbits, 1, 1,
vec2_huffcodes, 2, 2, 562);
INIT_VLC_STATIC(&vec1_vlc, VLCBITS, HUFF_VEC1_SIZE,
vec1_huffbits, 1, 1,
vec1_huffcodes, 2, 2, 562);
/** calculate number of scale factor bands and their offsets /** calculate number of scale factor bands and their offsets
for every possible block size */ for every possible block size */
for (i = 0; i < num_possible_block_sizes; i++) { for (i = 0; i < num_possible_block_sizes; i++) {
@ -554,7 +560,6 @@ static av_cold int decode_init(WMAProDecodeCtx *s, AVCodecContext *avctx, int nu
/** init MDCT windows: simple sine window */ /** init MDCT windows: simple sine window */
for (i = 0; i < WMAPRO_BLOCK_SIZES; i++) { for (i = 0; i < WMAPRO_BLOCK_SIZES; i++) {
const int win_idx = WMAPRO_BLOCK_MAX_BITS - i; const int win_idx = WMAPRO_BLOCK_MAX_BITS - i;
ff_init_ff_sine_windows(win_idx);
s->windows[WMAPRO_BLOCK_SIZES - i - 1] = ff_sine_windows[win_idx]; s->windows[WMAPRO_BLOCK_SIZES - i - 1] = ff_sine_windows[win_idx];
} }
@ -566,15 +571,13 @@ static av_cold int decode_init(WMAProDecodeCtx *s, AVCodecContext *avctx, int nu
s->subwoofer_cutoffs[i] = av_clip(cutoff, 4, block_size); s->subwoofer_cutoffs[i] = av_clip(cutoff, 4, block_size);
} }
/** calculate sine values for the decorrelation matrix */
for (i = 0; i < 33; i++)
sin64[i] = sin(i*M_PI / 64.0);
if (avctx->debug & FF_DEBUG_BITSTREAM) if (avctx->debug & FF_DEBUG_BITSTREAM)
dump_context(s); dump_context(s);
avctx->channel_layout = channel_mask; avctx->channel_layout = channel_mask;
ff_thread_once(&init_static_once, decode_init_static);
return 0; return 0;
} }
@ -2018,10 +2021,10 @@ const AVCodec ff_wmapro_decoder = {
.close = wmapro_decode_end, .close = wmapro_decode_end,
.decode = wmapro_decode_packet, .decode = wmapro_decode_packet,
.capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1, .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
.flush = wmapro_flush, .flush = wmapro_flush,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP, .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE }, AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
}; };
const AVCodec ff_xma1_decoder = { const AVCodec ff_xma1_decoder = {
@ -2034,9 +2037,9 @@ const AVCodec ff_xma1_decoder = {
.close = xma_decode_end, .close = xma_decode_end,
.decode = xma_decode_packet, .decode = xma_decode_packet,
.capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY, .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP, .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE }, AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
}; };
const AVCodec ff_xma2_decoder = { const AVCodec ff_xma2_decoder = {
@ -2050,7 +2053,7 @@ const AVCodec ff_xma2_decoder = {
.decode = xma_decode_packet, .decode = xma_decode_packet,
.flush = xma_flush, .flush = xma_flush,
.capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY, .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP, .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE }, AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
}; };

Write Preview
Loading…
Cancel
Save