avcodec/shorten: support decoding AIFF-C variant

Signed-off-by: Paul B Mahol <onemda@gmail.com>

configure

@@ -2513,7 +2513,7 @@ rv20_encoder_select="h263_encoder"
 rv30_decoder_select="golomb h264pred h264qpel mpegvideo rv34dsp"
 rv40_decoder_select="golomb h264pred h264qpel mpegvideo rv34dsp"
 screenpresso_decoder_select="zlib"
-shorten_decoder_select="golomb"
+shorten_decoder_select="golomb bswapdsp"
 sipr_decoder_select="lsp"
 snow_decoder_select="dwt h264qpel hpeldsp me_cmp rangecoder videodsp"
 snow_encoder_select="aandcttables dwt h264qpel hpeldsp me_cmp mpegvideoenc rangecoder"

libavcodec/shorten.c

@@ -27,6 +27,7 @@
 
 #include <limits.h>
 #include "avcodec.h"
+#include "bswapdsp.h"
 #include "bytestream.h"
 #include "get_bits.h"
 #include "golomb.h"
@@ -109,6 +110,8 @@ typedef struct ShortenContext {
     int32_t lpcqoffset;
     int got_header;
     int got_quit_command;
+    int swap;
+    BswapDSPContext bdsp;
 } ShortenContext;
 
 static av_cold int shorten_decode_init(AVCodecContext *avctx)
@@ -116,6 +119,8 @@ static av_cold int shorten_decode_init(AVCodecContext *avctx)
     ShortenContext *s = avctx->priv_data;
     s->avctx          = avctx;
 
+    ff_bswapdsp_init(&s->bdsp);
+
     return 0;
 }
 
@@ -202,6 +207,7 @@ static int init_offset(ShortenContext *s)
 static int decode_aiff_header(AVCodecContext *avctx, const uint8_t *header,
                               int header_size)
 {
+    ShortenContext *s = avctx->priv_data;
     int len, bps, exp;
     GetByteContext gb;
     uint64_t val;
@@ -217,7 +223,8 @@ static int decode_aiff_header(AVCodecContext *avctx, const uint8_t *header,
     bytestream2_skip(&gb, 4); /* chunk size */
 
     tag = bytestream2_get_le32(&gb);
-    if (tag != MKTAG('A', 'I', 'F', 'F')) {
+    if (tag != MKTAG('A', 'I', 'F', 'F') &&
+        tag != MKTAG('A', 'I', 'F', 'C')) {
         av_log(avctx, AV_LOG_ERROR, "missing AIFF tag\n");
         return AVERROR_INVALIDDATA;
     }
@@ -241,6 +248,8 @@ static int decode_aiff_header(AVCodecContext *avctx, const uint8_t *header,
     bps = bytestream2_get_be16(&gb);
     avctx->bits_per_coded_sample = bps;
 
+    s->swap = tag == MKTAG('A', 'I', 'F', 'C');
+
     if (bps != 16 && bps != 8) {
         av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample: %d\n", bps);
         return AVERROR(ENOSYS);
@@ -721,6 +730,11 @@ static int shorten_decode_frame(AVCodecContext *avctx, void *data,
                             break;
                         }
                     }
+                    if (s->swap && s->internal_ftype != TYPE_U8)
+                        s->bdsp.bswap16_buf(((uint16_t **)frame->extended_data)[chan],
+                                            ((uint16_t **)frame->extended_data)[chan],
+                                            s->blocksize);
+
                 }
 
                 *got_frame_ptr = 1;