[FFmpeg-devel] [PATCH] avformat/dv: allow returning damaged audio
Michael Niedermayer
michael at niedermayer.cc
Thu Oct 29 23:58:38 EET 2020
These potentially damaged packets are marked as corrupt.
The packet length is predicted based on packet length history,
allowing prediction of the common pattern used in NTSC.
Fixes: Ticket8762
Tested-by: Dave Rice <dave at dericed.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
libavformat/dv.c | 60 ++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 53 insertions(+), 7 deletions(-)
diff --git a/libavformat/dv.c b/libavformat/dv.c
index 3e0d12c0e3..3499cba6f8 100644
--- a/libavformat/dv.c
+++ b/libavformat/dv.c
@@ -34,12 +34,20 @@
#include "libavcodec/dv_profile.h"
#include "libavcodec/dv.h"
#include "libavutil/channel_layout.h"
+#include "libavutil/opt.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "libavutil/timecode.h"
#include "dv.h"
#include "libavutil/avassert.h"
+#define AS_HASH_SIZE 16
+
+enum AudioConceal {
+ AUDIO_CONCEAL_PASS = 1,
+ AUDIO_CONCEAL_DROP = 0,
+};
+
struct DVDemuxContext {
const AVDVProfile* sys; /* Current DV profile. E.g.: 525/60, 625/50 */
AVFormatContext* fctx;
@@ -50,6 +58,9 @@ struct DVDemuxContext {
int ach;
int frames;
uint64_t abytes;
+ uint8_t as_pack[AS_HASH_SIZE][5];
+ uint8_t as_hash;
+ int dvaudio_concealment;
};
static inline uint16_t dv_audio_12to16(uint16_t sample)
@@ -72,7 +83,7 @@ static inline uint16_t dv_audio_12to16(uint16_t sample)
return result;
}
-static const uint8_t *dv_extract_pack(const uint8_t *frame, enum dv_pack_type t)
+static const uint8_t *dv_extract_pack(DVDemuxContext *d, const uint8_t *frame, enum dv_pack_type t)
{
int offs;
int c;
@@ -101,6 +112,17 @@ static const uint8_t *dv_extract_pack(const uint8_t *frame, enum dv_pack_type t)
break;
}
+ if (t == dv_audio_source || t == dv_audio_control) {
+ int index = (d->as_hash>>1) & (AS_HASH_SIZE-1);
+ if (frame[offs] == t) {
+ memcpy(d->as_pack[index], &frame[offs], sizeof(d->as_pack[index]));
+ } else if (d->as_pack[index][0] && d->dvaudio_concealment == AUDIO_CONCEAL_PASS) {
+ return d->as_pack[index];
+ } else if (d->as_pack[0][0] && d->dvaudio_concealment == AUDIO_CONCEAL_PASS) {
+ return d->as_pack[0];
+ }
+ }
+
return frame[offs] == t ? &frame[offs] : NULL;
}
@@ -116,7 +138,7 @@ static const int dv_audio_frequency[3] = {
* 3. Audio is always returned as 16-bit linear samples: 12-bit nonlinear samples
* are converted into 16-bit linear ones.
*/
-static int dv_extract_audio(const uint8_t *frame, uint8_t **ppcm,
+static int dv_extract_audio(DVDemuxContext *c, const uint8_t *frame, uint8_t **ppcm,
const AVDVProfile *sys)
{
int size, chan, i, j, d, of, smpls, freq, quant, half_ch;
@@ -124,7 +146,7 @@ static int dv_extract_audio(const uint8_t *frame, uint8_t **ppcm,
const uint8_t *as_pack;
uint8_t *pcm, ipcm;
- as_pack = dv_extract_pack(frame, dv_audio_source);
+ as_pack = dv_extract_pack(c, frame, dv_audio_source);
if (!as_pack) /* No audio ? */
return 0;
@@ -137,6 +159,7 @@ static int dv_extract_audio(const uint8_t *frame, uint8_t **ppcm,
if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency))
return AVERROR_INVALIDDATA;
+ c->as_hash = 2*c->as_hash + smpls;
size = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
half_ch = sys->difseg_size / 2;
@@ -153,6 +176,9 @@ static int dv_extract_audio(const uint8_t *frame, uint8_t **ppcm,
/* for each DIF channel */
for (chan = 0; chan < sys->n_difchan; chan++) {
av_assert0(ipcm<4);
+ c->audio_pkt[ipcm].flags &= ~AV_PKT_FLAG_CORRUPT;
+ if (as_pack >= c->as_pack[0] && as_pack < c->as_pack[AS_HASH_SIZE])
+ c->audio_pkt[ipcm].flags |= AV_PKT_FLAG_CORRUPT;
pcm = ppcm[ipcm++];
if (!pcm)
break;
@@ -224,7 +250,7 @@ static int dv_extract_audio_info(DVDemuxContext *c, const uint8_t *frame)
const uint8_t *as_pack;
int freq, stype, smpls, quant, i, ach;
- as_pack = dv_extract_pack(frame, dv_audio_source);
+ as_pack = dv_extract_pack(c, frame, dv_audio_source);
if (!as_pack || !c->sys) { /* No audio ? */
c->ach = 0;
return 0;
@@ -292,7 +318,7 @@ static int dv_extract_video_info(DVDemuxContext *c, const uint8_t *frame)
c->vst->avg_frame_rate = av_inv_q(c->vst->time_base);
/* finding out SAR is a little bit messy */
- vsc_pack = dv_extract_pack(frame, dv_video_control);
+ vsc_pack = dv_extract_pack(c, frame, dv_video_control);
apt = frame[4] & 0x07;
is16_9 = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
(!apt && (vsc_pack[2] & 0x07) == 0x07)));
@@ -312,7 +338,7 @@ static int dv_extract_timecode(DVDemuxContext* c, const uint8_t* frame, char *tc
// is only relevant for NTSC systems.
int prevent_df = c->sys->ltc_divisor == 25 || c->sys->ltc_divisor == 50;
- tc_pack = dv_extract_pack(frame, dv_timecode);
+ tc_pack = dv_extract_pack(c, frame, dv_timecode);
if (!tc_pack)
return 0;
av_timecode_make_smpte_tc_string2(tc, av_inv_q(c->sys->time_base), AV_RB32(tc_pack + 1), prevent_df, 1);
@@ -392,7 +418,7 @@ int avpriv_dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
ppcm[i] = c->audio_buf[i];
}
if (c->ach)
- dv_extract_audio(buf, ppcm, c->sys);
+ dv_extract_audio(c, buf, ppcm, c->sys);
/* We work with 720p frames split in half, thus even frames have
* channels 0,1 and odd 2,3. */
@@ -460,8 +486,10 @@ void ff_dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
************************************************************/
typedef struct RawDVContext {
+ const AVClass *class;
DVDemuxContext dv_demux;
uint8_t buf[DV_MAX_FRAME_SIZE];
+ int dvaudio_concealment;
} RawDVContext;
static int dv_read_timecode(AVFormatContext *s) {
@@ -502,6 +530,7 @@ static int dv_read_header(AVFormatContext *s)
if ((ret = dv_init_demux(s, &c->dv_demux)) < 0)
return ret;
+ c->dv_demux.dvaudio_concealment = c->dvaudio_concealment;
state = avio_rb32(s->pb);
while ((state & 0xffffff7f) != 0x1f07003f) {
@@ -626,6 +655,22 @@ static int dv_probe(const AVProbeData *p)
return 0;
}
+#define OFFSET(x) offsetof(RawDVContext, x)
+#define DEC AV_OPT_FLAG_DECODING_PARAM
+static const AVOption dv_options[] = {
+ { "dvaudio_concealment", "", OFFSET(dvaudio_concealment), AV_OPT_TYPE_INT , {.i64 = AUDIO_CONCEAL_DROP}, 0, INT_MAX, DEC, "dvaudio_concealment"},
+ { "drop", "", 0 , AV_OPT_TYPE_CONST, {.i64 = AUDIO_CONCEAL_DROP}, 0, INT_MAX, DEC, "dvaudio_concealment"},
+ { "pass", "", 0 , AV_OPT_TYPE_CONST, {.i64 = AUDIO_CONCEAL_PASS}, 0, INT_MAX, DEC, "dvaudio_concealment"},
+ { NULL },
+};
+
+static const AVClass dv_demuxer_class = {
+ .class_name = "DV demuxer",
+ .item_name = av_default_item_name,
+ .option = dv_options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
AVInputFormat ff_dv_demuxer = {
.name = "dv",
.long_name = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
@@ -635,4 +680,5 @@ AVInputFormat ff_dv_demuxer = {
.read_packet = dv_read_packet,
.read_seek = dv_read_seek,
.extensions = "dv,dif",
+ .priv_class = &dv_demuxer_class,
};
--
2.17.1
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