X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Falac.c;h=5c48a4b28f4a105a8a34dcc602e8bddf788ef90a;hb=b07781b6e4f6267f20aec4e7f1d390ddb223af46;hp=219dcefab2116e65832fb1789e32e134ff63e327;hpb=26df3ba28c0a5f6d10ef9035b4be1c28b20d2655;p=ffmpeg diff --git a/libavcodec/alac.c b/libavcodec/alac.c index 219dcefab21..5c48a4b28f4 100644 --- a/libavcodec/alac.c +++ b/libavcodec/alac.c @@ -20,7 +20,7 @@ */ /** - * @file alac.c + * @file libavcodec/alac.c * ALAC (Apple Lossless Audio Codec) decoder * @author 2005 David Hammerton * @@ -53,9 +53,10 @@ #include "avcodec.h" -#include "bitstream.h" +#include "get_bits.h" #include "bytestream.h" #include "unary.h" +#include "mathops.h" #define ALAC_EXTRADATA_SIZE 36 #define MAX_CHANNELS 2 @@ -68,7 +69,6 @@ typedef struct { * set this to 1 */ int context_initialized; - int samplesize; int numchannels; int bytespersample; @@ -79,16 +79,10 @@ typedef struct { /* stuff from setinfo */ uint32_t setinfo_max_samples_per_frame; /* 0x1000 = 4096 */ /* max samples per frame? */ - uint8_t setinfo_7a; /* 0x00 */ uint8_t setinfo_sample_size; /* 0x10 */ uint8_t setinfo_rice_historymult; /* 0x28 */ uint8_t setinfo_rice_initialhistory; /* 0x0a */ uint8_t setinfo_rice_kmodifier; /* 0x0e */ - uint8_t setinfo_7f; /* 0x02 */ - uint16_t setinfo_80; /* 0x00ff */ - uint32_t setinfo_82; /* 0x000020e7 */ /* max sample size?? */ - uint32_t setinfo_86; /* 0x00069fe4 */ /* bit rate (average)?? */ - uint32_t setinfo_8a_rate; /* 0x0000ac44 */ /* end setinfo stuff */ } ALACContext; @@ -120,29 +114,51 @@ static int alac_set_info(ALACContext *alac) /* buffer size / 2 ? */ alac->setinfo_max_samples_per_frame = bytestream_get_be32(&ptr); - alac->setinfo_7a = *ptr++; + ptr++; /* ??? */ alac->setinfo_sample_size = *ptr++; + if (alac->setinfo_sample_size > 32) { + av_log(alac->avctx, AV_LOG_ERROR, "setinfo_sample_size too large\n"); + return -1; + } alac->setinfo_rice_historymult = *ptr++; alac->setinfo_rice_initialhistory = *ptr++; alac->setinfo_rice_kmodifier = *ptr++; - /* channels? */ - alac->setinfo_7f = *ptr++; - alac->setinfo_80 = bytestream_get_be16(&ptr); - /* max coded frame size */ - alac->setinfo_82 = bytestream_get_be32(&ptr); - /* bitrate ? */ - alac->setinfo_86 = bytestream_get_be32(&ptr); - /* samplerate */ - alac->setinfo_8a_rate = bytestream_get_be32(&ptr); + ptr++; /* channels? */ + bytestream_get_be16(&ptr); /* ??? */ + bytestream_get_be32(&ptr); /* max coded frame size */ + bytestream_get_be32(&ptr); /* bitrate ? */ + bytestream_get_be32(&ptr); /* samplerate */ allocate_buffers(alac); return 0; } -static inline int count_leading_zeros(int32_t input) -{ - return 31-av_log2(input); +static inline int decode_scalar(GetBitContext *gb, int k, int limit, int readsamplesize){ + /* read x - number of 1s before 0 represent the rice */ + int x = get_unary_0_9(gb); + + if (x > 8) { /* RICE THRESHOLD */ + /* use alternative encoding */ + x = get_bits(gb, readsamplesize); + } else { + if (k >= limit) + k = limit; + + if (k != 1) { + int extrabits = show_bits(gb, k); + + /* multiply x by 2^k - 1, as part of their strange algorithm */ + x = (x << k) - x; + + if (extrabits > 1) { + x += extrabits - 1; + skip_bits(gb, k); + } else + skip_bits(gb, k - 1); + } + } + return x; } static void bastardized_rice_decompress(ALACContext *alac, @@ -164,36 +180,12 @@ static void bastardized_rice_decompress(ALACContext *alac, int32_t x_modified; int32_t final_val; - /* read x - number of 1s before 0 represent the rice */ - x = get_unary_0_9(&alac->gb); + /* standard rice encoding */ + int k; /* size of extra bits */ - if (x > 8) { /* RICE THRESHOLD */ - /* use alternative encoding */ - x = get_bits(&alac->gb, readsamplesize); - } else { - /* standard rice encoding */ - int extrabits; - int k; /* size of extra bits */ - - /* read k, that is bits as is */ - k = 31 - count_leading_zeros((history >> 9) + 3); - - if (k >= rice_kmodifier) - k = rice_kmodifier; - - if (k != 1) { - extrabits = show_bits(&alac->gb, k); - - /* multiply x by 2^k - 1, as part of their strange algorithm */ - x = (x << k) - x; - - if (extrabits > 1) { - x += extrabits - 1; - skip_bits(&alac->gb, k); - } else - skip_bits(&alac->gb, k - 1); - } - } + /* read k, that is bits as is */ + k = av_log2((history >> 9) + 3); + x= decode_scalar(&alac->gb, k, rice_kmodifier, readsamplesize); x_modified = sign_modifier + x; final_val = (x_modified + 1) / 2; @@ -212,36 +204,20 @@ static void bastardized_rice_decompress(ALACContext *alac, /* special case: there may be compressed blocks of 0 */ if ((history < 128) && (output_count+1 < output_size)) { - int block_size; + int k; + unsigned int block_size; sign_modifier = 1; - x = get_unary_0_9(&alac->gb); - - if (x > 8) { - block_size = get_bits(&alac->gb, 16); - block_size &= 0xffff; - } else { - int k; - int extrabits; - - k = count_leading_zeros(history) + ((history + 16) >> 6 /* / 64 */) - 24; + k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */); - extrabits = show_bits(&alac->gb, k); - - block_size = (((1 << k) - 1) & rice_kmodifier_mask) * x - + extrabits - 1; - - if (extrabits < 2) { - x = 1 - extrabits; - block_size += x; - skip_bits(&alac->gb, k - 1); - } else { - skip_bits(&alac->gb, k); - } - } + block_size= decode_scalar(&alac->gb, k, rice_kmodifier, 16); if (block_size > 0) { + if(block_size >= output_size - output_count){ + av_log(alac->avctx, AV_LOG_ERROR, "invalid zero block size of %d %d %d\n", block_size, output_size, output_count); + block_size= output_size - output_count - 1; + } memset(&output_buffer[output_count+1], 0, block_size * 4); output_count += block_size; } @@ -254,11 +230,6 @@ static void bastardized_rice_decompress(ALACContext *alac, } } -static inline int32_t extend_sign32(int32_t val, int bits) -{ - return (val << (32 - bits)) >> (32 - bits); -} - static inline int sign_only(int v) { return v ? FFSIGN(v) : 0; @@ -298,7 +269,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer, prev_value = buffer_out[i]; error_value = error_buffer[i+1]; buffer_out[i+1] = - extend_sign32((prev_value + error_value), readsamplesize); + sign_extend((prev_value + error_value), readsamplesize); } return; } @@ -309,7 +280,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer, int32_t val; val = buffer_out[i] + error_buffer[i+1]; - val = extend_sign32(val, readsamplesize); + val = sign_extend(val, readsamplesize); buffer_out[i+1] = val; } @@ -344,7 +315,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer, outval = (1 << (predictor_quantitization-1)) + sum; outval = outval >> predictor_quantitization; outval = outval + buffer_out[0] + error_val; - outval = extend_sign32(outval, readsamplesize); + outval = sign_extend(outval, readsamplesize); buffer_out[predictor_coef_num+1] = outval; @@ -429,14 +400,16 @@ static void reconstruct_stereo_16(int32_t *buffer[MAX_CHANNELS], static int alac_decode_frame(AVCodecContext *avctx, void *outbuffer, int *outputsize, - const uint8_t *inbuffer, int input_buffer_size) + AVPacket *avpkt) { + const uint8_t *inbuffer = avpkt->data; + int input_buffer_size = avpkt->size; ALACContext *alac = avctx->priv_data; int channels; - int32_t outputsamples; + unsigned int outputsamples; int hassize; - int readsamplesize; + unsigned int readsamplesize; int wasted_bytes; int isnotcompressed; uint8_t interlacing_shift; @@ -486,12 +459,25 @@ static int alac_decode_frame(AVCodecContext *avctx, if (hassize) { /* now read the number of samples as a 32bit integer */ - outputsamples = get_bits(&alac->gb, 32); + outputsamples = get_bits_long(&alac->gb, 32); + if(outputsamples > alac->setinfo_max_samples_per_frame){ + av_log(avctx, AV_LOG_ERROR, "outputsamples %d > %d\n", outputsamples, alac->setinfo_max_samples_per_frame); + return -1; + } } else outputsamples = alac->setinfo_max_samples_per_frame; + if(outputsamples > *outputsize / alac->bytespersample){ + av_log(avctx, AV_LOG_ERROR, "sample buffer too small\n"); + return -1; + } + *outputsize = outputsamples * alac->bytespersample; readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8) + channels - 1; + if (readsamplesize > MIN_CACHE_BITS) { + av_log(avctx, AV_LOG_ERROR, "readsamplesize too big (%d)\n", readsamplesize); + return -1; + } if (!isnotcompressed) { /* so it is compressed */ @@ -551,37 +537,21 @@ static int alac_decode_frame(AVCodecContext *avctx, } } else { /* not compressed, easy case */ - if (alac->setinfo_sample_size <= 16) { - int i, chan; - for (chan = 0; chan < channels; chan++) - for (i = 0; i < outputsamples; i++) { - int32_t audiobits; + int i, chan; + for (i = 0; i < outputsamples; i++) + for (chan = 0; chan < channels; chan++) { + int32_t audiobits; - audiobits = get_bits(&alac->gb, alac->setinfo_sample_size); - audiobits = extend_sign32(audiobits, readsamplesize); + audiobits = get_sbits_long(&alac->gb, alac->setinfo_sample_size); - alac->outputsamples_buffer[chan][i] = audiobits; - } - } else { - int i, chan; - for (chan = 0; chan < channels; chan++) - for (i = 0; i < outputsamples; i++) { - int32_t audiobits; - - audiobits = get_bits(&alac->gb, 16); - /* special case of sign extension.. - * as we'll be ORing the low 16bits into this */ - audiobits = audiobits << 16; - audiobits = audiobits >> (32 - alac->setinfo_sample_size); - audiobits |= get_bits(&alac->gb, alac->setinfo_sample_size - 16); - - alac->outputsamples_buffer[chan][i] = audiobits; - } - } + alac->outputsamples_buffer[chan][i] = audiobits; + } /* wasted_bytes = 0; */ interlacing_shift = 0; interlacing_leftweight = 0; } + if (get_bits(&alac->gb, 3) != 7) + av_log(avctx, AV_LOG_ERROR, "Error : Wrong End Of Frame\n"); switch(alac->setinfo_sample_size) { case 16: @@ -611,6 +581,9 @@ static int alac_decode_frame(AVCodecContext *avctx, break; } + if (input_buffer_size * 8 - get_bits_count(&alac->gb) > 8) + av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n", input_buffer_size * 8 - get_bits_count(&alac->gb)); + return input_buffer_size; } @@ -620,9 +593,9 @@ static av_cold int alac_decode_init(AVCodecContext * avctx) alac->avctx = avctx; alac->context_initialized = 0; - alac->samplesize = alac->avctx->bits_per_sample; alac->numchannels = alac->avctx->channels; - alac->bytespersample = (alac->samplesize / 8) * alac->numchannels; + alac->bytespersample = 2 * alac->numchannels; + avctx->sample_fmt = SAMPLE_FMT_S16; return 0; } @@ -649,4 +622,5 @@ AVCodec alac_decoder = { NULL, alac_decode_close, alac_decode_frame, + .long_name = NULL_IF_CONFIG_SMALL("ALAC (Apple Lossless Audio Codec)"), };