[FFmpeg-devel] [PATCH] avcodec/wmaprodec: improve WMAPRO/XMA gapless output
bananaman255 at gmail.com
bananaman255 at gmail.com
Wed Oct 10 02:15:02 EEST 2018
From: bnnm <bananaman255 at gmail.com>
Improves trac issue #6722. Fixes truncated WMAPRO/XMA output due to delay samples and partially applies bitstream gapless info.
This can be tested with files encoding a small nb_samples (like 400), which couldn't output anything due to missing delay at the end.
Applying end_skip and partial delay samples would require some extra changes, so files are slightly bigger than what should be.
Signed-off-by: bnnm <bananaman255 at gmail.com>
---
libavcodec/wmaprodec.c | 100 ++++++++++++++++++++++++++++++++++++-------------
tests/fate/wma.mak | 1 +
2 files changed, 74 insertions(+), 27 deletions(-)
diff --git a/libavcodec/wmaprodec.c b/libavcodec/wmaprodec.c
index 9439bfa771..e18e2e438f 100644
--- a/libavcodec/wmaprodec.c
+++ b/libavcodec/wmaprodec.c
@@ -216,9 +216,9 @@ typedef struct WMAProDecodeCtx {
GetBitContext gb; ///< bitstream reader context
int buf_bit_size; ///< buffer size in bits
uint8_t drc_gain; ///< gain for the DRC tool
- int8_t skip_frame; ///< skip output step
int8_t parsed_all_subframes; ///< all subframes decoded?
uint8_t skip_packets; ///< packets to skip to find next packet in a stream (XMA1/2)
+ int8_t eof_done; ///< set when EOF reached and extra subframe is written (XMA1/2)
/* subframe/block decode state */
int16_t subframe_len; ///< current subframe length
@@ -379,12 +379,6 @@ static av_cold int decode_init(WMAProDecodeCtx *s, AVCodecContext *avctx, int nu
return AVERROR_PATCHWELCOME;
}
- /** frame info */
- if (avctx->codec_id != AV_CODEC_ID_WMAPRO)
- s->skip_frame = 0;
- else
- s->skip_frame = 1; /* skip first frame */
-
s->packet_loss = 1;
s->len_prefix = (s->decode_flags & 0x40);
@@ -1450,21 +1444,38 @@ static int decode_frame(WMAProDecodeCtx *s, AVFrame *frame, int *got_frame_ptr)
ff_dlog(s->avctx, "drc_gain %i\n", s->drc_gain);
}
- /** no idea what these are for, might be the number of samples
- that need to be skipped at the beginning or end of a stream */
+ /** read encoder delay/padding (gapless) info */
if (get_bits1(gb)) {
- int av_unused skip;
+ int start_skip, end_skip;
+
- /** usually true for the first frame */
+ /** usually true for the first frame and equal to 1 frame */
if (get_bits1(gb)) {
- skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
- ff_dlog(s->avctx, "start skip: %i\n", skip);
+ start_skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
+ start_skip = FFMIN(start_skip, s->samples_per_frame);
+
+ /* must add for XMA to respect starting skip_samples */
+ s->avctx->internal->skip_samples += start_skip;
}
- /** sometimes true for the last frame */
+ /** usually true for the last frame and less than 1 frame */
if (get_bits1(gb)) {
- skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
- ff_dlog(s->avctx, "end skip: %i\n", skip);
+ end_skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
+ end_skip = FFMIN(end_skip, s->samples_per_frame);
+
+ //TODO fix end_skip (also needs changes in XMA multistream's handling)
+ /* for XMA/WMAPRO end_skip may span last frame + final delay samples,
+ * so we'd need some counter to (possibly) skip some in this frame and
+ * rest after last frame (buf_size 0), so final samples would be:
+ * samples_per_frame + delay_samples - start_skip - end_skip
+ * (files with 1 packet are possible so both skips are considered).
+ *
+ * WMAPRO 5.1 in XWMA does't do this and audio is padded instead,
+ * and min packets is 2 (assumes only 1/2ch need it). */
+
+ if (s->avctx->codec_id == AV_CODEC_ID_WMAPRO && s->nb_channels > 2) {
+ frame->nb_samples = s->samples_per_frame - end_skip;
+ }
}
}
@@ -1500,13 +1511,9 @@ static int decode_frame(WMAProDecodeCtx *s, AVFrame *frame, int *got_frame_ptr)
s->samples_per_frame * sizeof(*s->channel[i].out) >> 1);
}
- if (s->skip_frame) {
- s->skip_frame = 0;
- *got_frame_ptr = 0;
- av_frame_unref(frame);
- } else {
- *got_frame_ptr = 1;
- }
+ /** frame may be partially discarded with gapless info in the bitstream */
+ *got_frame_ptr = 1;
+
if (s->len_prefix) {
if (len != (get_bits_count(gb) - s->frame_offset) + 2) {
@@ -1609,7 +1616,35 @@ static int decode_packet(AVCodecContext *avctx, WMAProDecodeCtx *s,
*got_frame_ptr = 0;
- if (s->packet_done || s->packet_loss) {
+ if (!buf_size) {
+ AVFrame *frame = data;
+ int i;
+
+ /** Must output remaining samples after stream end. WMAPRO 5.1 created
+ * by XWMA encoder don't though; assuming only 1/2ch streams need it. */
+ s->packet_done = 0;
+ if (s->eof_done || s->nb_channels > 2)
+ return 0;
+
+ /** clean output buffer and copy last IMCDT samples */
+ for (i = 0; i < s->nb_channels; i++) {
+ memset(frame->extended_data[i], 0,
+ s->samples_per_frame * sizeof(*s->channel[i].out));
+
+ memcpy(frame->extended_data[i], s->channel[i].out,
+ s->samples_per_frame * sizeof(*s->channel[i].out) >> 1);
+ }
+
+ /* TODO: change nb_samples to delay_samples. XMA always uses 128
+ * (with 512 samples per frame) and WMAPRO may use 768 (2048 s.p.f.).
+ * XMA needs changes in multi-stream handling though. */
+
+ s->eof_done = 1;
+ s->packet_done = 1;
+ *got_frame_ptr = 1;
+ return 0;
+ }
+ else if (s->packet_done || s->packet_loss) {
s->packet_done = 0;
/** sanity check for the buffer length */
@@ -1896,6 +1931,12 @@ static av_cold int xma_decode_init(AVCodecContext *avctx)
start_channels += s->xma[i].nb_channels;
}
+ /** XMA seems to require this to create gapless files (WMAPRO encoder
+ * pads files with silence, while XMA can encode any nb_samples).
+ * This value seems to counter the extra subframe output at EOF
+ * (or perhaps, XMA decoder should output 64 samples earlier?) */
+ avctx->internal->skip_samples = 128/2;
+
return ret;
}
@@ -1922,6 +1963,7 @@ static void flush(WMAProDecodeCtx *s)
sizeof(*s->channel[i].out));
s->packet_loss = 1;
s->skip_packets = 0;
+ s->eof_done = 0;
}
@@ -1934,6 +1976,8 @@ static void wmapro_flush(AVCodecContext *avctx)
WMAProDecodeCtx *s = avctx->priv_data;
flush(s);
+
+ avctx->internal->skip_samples = 0;
}
static void xma_flush(AVCodecContext *avctx)
@@ -1946,6 +1990,8 @@ static void xma_flush(AVCodecContext *avctx)
memset(s->offset, 0, sizeof(s->offset));
s->current_stream = 0;
+
+ avctx->internal->skip_samples = 128/2;
}
@@ -1961,7 +2007,7 @@ AVCodec ff_wmapro_decoder = {
.init = wmapro_decode_init,
.close = wmapro_decode_end,
.decode = wmapro_decode_packet,
- .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,
+ .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
.flush = wmapro_flush,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE },
@@ -1976,7 +2022,7 @@ AVCodec ff_xma1_decoder = {
.init = xma_decode_init,
.close = xma_decode_end,
.decode = xma_decode_packet,
- .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,
+ .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE },
};
@@ -1991,7 +2037,7 @@ AVCodec ff_xma2_decoder = {
.close = xma_decode_end,
.decode = xma_decode_packet,
.flush = xma_flush,
- .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,
+ .capabilities = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE },
};
diff --git a/tests/fate/wma.mak b/tests/fate/wma.mak
index 12a8fa989a..9c7ce6fd7d 100644
--- a/tests/fate/wma.mak
+++ b/tests/fate/wma.mak
@@ -11,6 +11,7 @@ fate-wmapro-5.1: SIZE_TOLERANCE = 24576
FATE_WMAPRO-$(call DEMDEC, MOV, WMAPRO) += fate-wmapro-ism
fate-wmapro-ism: CMD = pcm -i $(TARGET_SAMPLES)/isom/vc1-wmapro.ism -vn
fate-wmapro-ism: REF = $(SAMPLES)/isom/vc1-wmapro.pcm
+fate-wmapro-ism: SIZE_TOLERANCE = 12976
$(FATE_WMAPRO-yes): CMP = oneoff
--
2.11.0.windows.3
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