diff --git a/libavcodec/dcadec.c b/libavcodec/dcadec.c
index 741f2f766dd176b9172a36e4a6e56802db711468..2302a05fff858e0d66fa1ff369290f0db44eb1b3 100644
--- a/libavcodec/dcadec.c
+++ b/libavcodec/dcadec.c
@@ -1453,6 +1453,114 @@ static float dca_dmix_code(unsigned code)
return ((ff_dca_dmixtable[code] ^ sign) - sign) * (1.0 / (1 << 15));
}
+static int scan_for_extensions(AVCodecContext *avctx)
+{
+ DCAContext *s = avctx->priv_data;
+ int core_ss_end, ret;
+
+ core_ss_end = FFMIN(s->frame_size, s->dca_buffer_size) * 8;
+
+ /* only scan for extensions if ext_descr was unknown or indicated a
+ * supported XCh extension */
+ if (s->core_ext_mask < 0 || s->core_ext_mask & (DCA_EXT_XCH | DCA_EXT_XXCH)) {
+ /* if ext_descr was unknown, clear s->core_ext_mask so that the
+ * extensions scan can fill it up */
+ s->core_ext_mask = FFMAX(s->core_ext_mask, 0);
+
+ /* extensions start at 32-bit boundaries into bitstream */
+ skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
+
+ while (core_ss_end - get_bits_count(&s->gb) >= 32) {
+ uint32_t bits = get_bits_long(&s->gb, 32);
+ int i;
+
+ switch (bits) {
+ case DCA_SYNCWORD_XCH: {
+ int ext_amode, xch_fsize;
+
+ s->xch_base_channel = s->prim_channels;
+
+ /* validate sync word using XCHFSIZE field */
+ xch_fsize = show_bits(&s->gb, 10);
+ if ((s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + xch_fsize) &&
+ (s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + xch_fsize + 1))
+ continue;
+
+ /* skip length-to-end-of-frame field for the moment */
+ skip_bits(&s->gb, 10);
+
+ s->core_ext_mask |= DCA_EXT_XCH;
+
+ /* extension amode(number of channels in extension) should be 1 */
+ /* AFAIK XCh is not used for more channels */
+ if ((ext_amode = get_bits(&s->gb, 4)) != 1) {
+ av_log(avctx, AV_LOG_ERROR,
+ "XCh extension amode %d not supported!\n",
+ ext_amode);
+ continue;
+ }
+
+ if (s->xch_base_channel < 2) {
+ avpriv_request_sample(avctx, "XCh with fewer than 2 base channels");
+ continue;
+ }
+
+ /* much like core primary audio coding header */
+ dca_parse_audio_coding_header(s, s->xch_base_channel, 0);
+
+ for (i = 0; i < (s->sample_blocks / 8); i++)
+ if ((ret = dca_decode_block(s, s->xch_base_channel, i))) {
+ av_log(avctx, AV_LOG_ERROR, "error decoding XCh extension\n");
+ continue;
+ }
+
+ s->xch_present = 1;
+ break;
+ }
+ case DCA_SYNCWORD_XXCH:
+ /* XXCh: extended channels */
+ /* usually found either in core or HD part in DTS-HD HRA streams,
+ * but not in DTS-ES which contains XCh extensions instead */
+ s->core_ext_mask |= DCA_EXT_XXCH;
+ ff_dca_xxch_decode_frame(s);
+ break;
+
+ case 0x1d95f262: {
+ int fsize96 = show_bits(&s->gb, 12) + 1;
+ if (s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + fsize96)
+ continue;
+
+ av_log(avctx, AV_LOG_DEBUG, "X96 extension found at %d bits\n",
+ get_bits_count(&s->gb));
+ skip_bits(&s->gb, 12);
+ av_log(avctx, AV_LOG_DEBUG, "FSIZE96 = %d bytes\n", fsize96);
+ av_log(avctx, AV_LOG_DEBUG, "REVNO = %d\n", get_bits(&s->gb, 4));
+
+ s->core_ext_mask |= DCA_EXT_X96;
+ break;
+ }
+ }
+
+ skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
+ }
+ } else {
+ /* no supported extensions, skip the rest of the core substream */
+ skip_bits_long(&s->gb, core_ss_end - get_bits_count(&s->gb));
+ }
+
+ if (s->core_ext_mask & DCA_EXT_X96)
+ s->profile = FF_PROFILE_DTS_96_24;
+ else if (s->core_ext_mask & (DCA_EXT_XCH | DCA_EXT_XXCH))
+ s->profile = FF_PROFILE_DTS_ES;
+
+ /* check for ExSS (HD part) */
+ if (s->dca_buffer_size - s->frame_size > 32 &&
+ get_bits_long(&s->gb, 32) == DCA_SYNCWORD_SUBSTREAM)
+ ff_dca_exss_parse_header(s);
+
+ return ret;
+}
+
/**
* Main frame decoding function
* FIXME add arguments
@@ -1472,7 +1580,6 @@ static int dca_decode_frame(AVCodecContext *avctx, void *data,
float *src_chan;
float *dst_chan;
DCAContext *s = avctx->priv_data;
- int core_ss_end;
int channels, full_channels;
float scale;
int achan;
@@ -1564,104 +1671,7 @@ static int dca_decode_frame(AVCodecContext *avctx, void *data,
else
s->core_ext_mask = 0;
- core_ss_end = FFMIN(s->frame_size, s->dca_buffer_size) * 8;
-
- /* only scan for extensions if ext_descr was unknown or indicated a
- * supported XCh extension */
- if (s->core_ext_mask < 0 || s->core_ext_mask & (DCA_EXT_XCH | DCA_EXT_XXCH)) {
- /* if ext_descr was unknown, clear s->core_ext_mask so that the
- * extensions scan can fill it up */
- s->core_ext_mask = FFMAX(s->core_ext_mask, 0);
-
- /* extensions start at 32-bit boundaries into bitstream */
- skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
-
- while (core_ss_end - get_bits_count(&s->gb) >= 32) {
- uint32_t bits = get_bits_long(&s->gb, 32);
-
- switch (bits) {
- case DCA_SYNCWORD_XCH: {
- int ext_amode, xch_fsize;
-
- s->xch_base_channel = s->prim_channels;
-
- /* validate sync word using XCHFSIZE field */
- xch_fsize = show_bits(&s->gb, 10);
- if ((s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + xch_fsize) &&
- (s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + xch_fsize + 1))
- continue;
-
- /* skip length-to-end-of-frame field for the moment */
- skip_bits(&s->gb, 10);
-
- s->core_ext_mask |= DCA_EXT_XCH;
-
- /* extension amode(number of channels in extension) should be 1 */
- /* AFAIK XCh is not used for more channels */
- if ((ext_amode = get_bits(&s->gb, 4)) != 1) {
- av_log(avctx, AV_LOG_ERROR,
- "XCh extension amode %d not supported!\n",
- ext_amode);
- continue;
- }
-
- if (s->xch_base_channel < 2) {
- avpriv_request_sample(avctx, "XCh with fewer than 2 base channels");
- continue;
- }
-
- /* much like core primary audio coding header */
- dca_parse_audio_coding_header(s, s->xch_base_channel, 0);
-
- for (i = 0; i < (s->sample_blocks / 8); i++)
- if ((ret = dca_decode_block(s, s->xch_base_channel, i))) {
- av_log(avctx, AV_LOG_ERROR, "error decoding XCh extension\n");
- continue;
- }
-
- s->xch_present = 1;
- break;
- }
- case DCA_SYNCWORD_XXCH:
- /* XXCh: extended channels */
- /* usually found either in core or HD part in DTS-HD HRA streams,
- * but not in DTS-ES which contains XCh extensions instead */
- s->core_ext_mask |= DCA_EXT_XXCH;
- ff_dca_xxch_decode_frame(s);
- break;
-
- case 0x1d95f262: {
- int fsize96 = show_bits(&s->gb, 12) + 1;
- if (s->frame_size != (get_bits_count(&s->gb) >> 3) - 4 + fsize96)
- continue;
-
- av_log(avctx, AV_LOG_DEBUG, "X96 extension found at %d bits\n",
- get_bits_count(&s->gb));
- skip_bits(&s->gb, 12);
- av_log(avctx, AV_LOG_DEBUG, "FSIZE96 = %d bytes\n", fsize96);
- av_log(avctx, AV_LOG_DEBUG, "REVNO = %d\n", get_bits(&s->gb, 4));
-
- s->core_ext_mask |= DCA_EXT_X96;
- break;
- }
- }
-
- skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
- }
- } else {
- /* no supported extensions, skip the rest of the core substream */
- skip_bits_long(&s->gb, core_ss_end - get_bits_count(&s->gb));
- }
-
- if (s->core_ext_mask & DCA_EXT_X96)
- s->profile = FF_PROFILE_DTS_96_24;
- else if (s->core_ext_mask & (DCA_EXT_XCH | DCA_EXT_XXCH))
- s->profile = FF_PROFILE_DTS_ES;
-
- /* check for ExSS (HD part) */
- if (s->dca_buffer_size - s->frame_size > 32 &&
- get_bits_long(&s->gb, 32) == DCA_SYNCWORD_SUBSTREAM)
- ff_dca_exss_parse_header(s);
+ ret = scan_for_extensions(avctx);
avctx->profile = s->profile;