[FFmpeg-cvslog] lavc: add support for filtering packets before decoding
Anton Khirnov
git at videolan.org
Sun Apr 23 04:56:40 EEST 2017
ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Sat Nov 12 17:43:55 2016 +0100| [972c71e9cb63e24f57ee481e413199c7d88a8813] | committer: Anton Khirnov
lavc: add support for filtering packets before decoding
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=972c71e9cb63e24f57ee481e413199c7d88a8813
---
configure | 1 +
libavcodec/avcodec.h | 6 ++
libavcodec/decode.c | 163 ++++++++++++++++++++++++++++++++++++++++++++++----
libavcodec/decode.h | 2 +
libavcodec/internal.h | 6 ++
libavcodec/utils.c | 3 +
6 files changed, 169 insertions(+), 12 deletions(-)
diff --git a/configure b/configure
index 6d809f7780..05047e9a15 100755
--- a/configure
+++ b/configure
@@ -2467,6 +2467,7 @@ transcode_aac_example_deps="avcodec avformat avresample"
# libraries, in linking order
avcodec_deps="avutil"
+avcodec_select="null_bsf"
avdevice_deps="avformat avcodec avutil"
avfilter_deps="avutil"
avformat_deps="avcodec avutil"
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 1827711b50..0997141e2c 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3243,6 +3243,12 @@ typedef struct AVCodec {
* See FF_CODEC_CAP_* in internal.h
*/
int caps_internal;
+
+ /**
+ * Decoding only, a comma-separated list of bitstream filters to apply to
+ * packets before decoding.
+ */
+ const char *bsfs;
} AVCodec;
/**
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index a1908ecf4b..0fd41ab482 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -154,6 +154,116 @@ static int unrefcount_frame(AVCodecInternal *avci, AVFrame *frame)
return 0;
}
+static int bsfs_init(AVCodecContext *avctx)
+{
+ AVCodecInternal *avci = avctx->internal;
+ DecodeFilterContext *s = &avci->filter;
+ const char *bsfs_str;
+ int ret;
+
+ if (s->nb_bsfs)
+ return 0;
+
+ bsfs_str = avctx->codec->bsfs ? avctx->codec->bsfs : "null";
+ while (bsfs_str && *bsfs_str) {
+ AVBSFContext **tmp;
+ const AVBitStreamFilter *filter;
+ char *bsf;
+
+ bsf = av_get_token(&bsfs_str, ",");
+ if (!bsf) {
+ ret = AVERROR(ENOMEM);
+ goto fail;
+ }
+
+ filter = av_bsf_get_by_name(bsf);
+ if (!filter) {
+ av_log(avctx, AV_LOG_ERROR, "A non-existing bitstream filter %s "
+ "requested by a decoder. This is a bug, please report it.\n",
+ bsf);
+ ret = AVERROR_BUG;
+ av_freep(&bsf);
+ goto fail;
+ }
+ av_freep(&bsf);
+
+ tmp = av_realloc_array(s->bsfs, s->nb_bsfs + 1, sizeof(*s->bsfs));
+ if (!tmp) {
+ ret = AVERROR(ENOMEM);
+ goto fail;
+ }
+ s->bsfs = tmp;
+ s->nb_bsfs++;
+
+ ret = av_bsf_alloc(filter, &s->bsfs[s->nb_bsfs - 1]);
+ if (ret < 0)
+ goto fail;
+
+ if (s->nb_bsfs == 1) {
+ /* We do not currently have an API for passing the input timebase into decoders,
+ * but no filters used here should actually need it.
+ * So we make up some plausible-looking number (the MPEG 90kHz timebase) */
+ s->bsfs[s->nb_bsfs - 1]->time_base_in = (AVRational){ 1, 90000 };
+ ret = avcodec_parameters_from_context(s->bsfs[s->nb_bsfs - 1]->par_in,
+ avctx);
+ } else {
+ s->bsfs[s->nb_bsfs - 1]->time_base_in = s->bsfs[s->nb_bsfs - 2]->time_base_out;
+ ret = avcodec_parameters_copy(s->bsfs[s->nb_bsfs - 1]->par_in,
+ s->bsfs[s->nb_bsfs - 2]->par_out);
+ }
+ if (ret < 0)
+ goto fail;
+
+ ret = av_bsf_init(s->bsfs[s->nb_bsfs - 1]);
+ if (ret < 0)
+ goto fail;
+ }
+
+ return 0;
+fail:
+ ff_decode_bsfs_uninit(avctx);
+ return ret;
+}
+
+/* try to get one output packet from the filter chain */
+static int bsfs_poll(AVCodecContext *avctx, AVPacket *pkt)
+{
+ DecodeFilterContext *s = &avctx->internal->filter;
+ int idx, ret;
+
+ /* start with the last filter in the chain */
+ idx = s->nb_bsfs - 1;
+ while (idx >= 0) {
+ /* request a packet from the currently selected filter */
+ ret = av_bsf_receive_packet(s->bsfs[idx], pkt);
+ if (ret == AVERROR(EAGAIN)) {
+ /* no packets available, try the next filter up the chain */
+ ret = 0;
+ idx--;
+ continue;
+ } else if (ret < 0 && ret != AVERROR_EOF) {
+ return ret;
+ }
+
+ /* got a packet or EOF -- pass it to the caller or to the next filter
+ * down the chain */
+ if (idx == s->nb_bsfs - 1) {
+ return ret;
+ } else {
+ idx++;
+ ret = av_bsf_send_packet(s->bsfs[idx], ret < 0 ? NULL : pkt);
+ if (ret < 0) {
+ av_log(avctx, AV_LOG_ERROR,
+ "Error pre-processing a packet before decoding\n");
+ av_packet_unref(pkt);
+ return ret;
+ }
+ }
+ }
+
+ return AVERROR(EAGAIN);
+}
+
int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt)
{
AVCodecInternal *avci = avctx->internal;
@@ -162,10 +272,11 @@ int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt)
if (avci->draining)
return AVERROR_EOF;
- if (!avci->buffer_pkt->data && !avci->buffer_pkt->side_data_elems)
- return AVERROR(EAGAIN);
-
- av_packet_move_ref(pkt, avci->buffer_pkt);
+ ret = bsfs_poll(avctx, pkt);
+ if (ret == AVERROR_EOF)
+ avci->draining = 1;
+ if (ret < 0)
+ return ret;
ret = extract_packet_props(avctx->internal, pkt);
if (ret < 0)
@@ -313,17 +424,23 @@ int attribute_align_arg avcodec_send_packet(AVCodecContext *avctx, const AVPacke
if (avctx->internal->draining)
return AVERROR_EOF;
- if (avci->buffer_pkt->data || avci->buffer_pkt->side_data_elems)
- return AVERROR(EAGAIN);
+ ret = bsfs_init(avctx);
+ if (ret < 0)
+ return ret;
- if (!avpkt || !avpkt->size) {
- avctx->internal->draining = 1;
- } else {
+ av_packet_unref(avci->buffer_pkt);
+ if (avpkt && (avpkt->data || avpkt->side_data_elems)) {
ret = av_packet_ref(avci->buffer_pkt, avpkt);
if (ret < 0)
return ret;
}
+ ret = av_bsf_send_packet(avci->filter.bsfs[0], avci->buffer_pkt);
+ if (ret < 0) {
+ av_packet_unref(avci->buffer_pkt);
+ return ret;
+ }
+
if (!avci->buffer_frame->buf[0]) {
ret = decode_receive_frame_internal(avctx, avci->buffer_frame);
if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
@@ -343,6 +460,10 @@ int attribute_align_arg avcodec_receive_frame(AVCodecContext *avctx, AVFrame *fr
if (!avcodec_is_open(avctx) || !av_codec_is_decoder(avctx->codec))
return AVERROR(EINVAL);
+ ret = bsfs_init(avctx);
+ if (ret < 0)
+ return ret;
+
if (avci->buffer_frame->buf[0]) {
av_frame_move_ref(frame, avci->buffer_frame);
} else {
@@ -415,13 +536,18 @@ static int compat_decode(AVCodecContext *avctx, AVFrame *frame,
}
}
- if (avci->draining || avci->compat_decode_consumed < pkt->size)
+ if (avci->draining || (!avctx->codec->bsfs && avci->compat_decode_consumed < pkt->size))
break;
}
finish:
- if (ret == 0)
- ret = FFMIN(avci->compat_decode_consumed, pkt->size);
+ if (ret == 0) {
+ /* if there are any bsfs then assume full packet is always consumed */
+ if (avctx->codec->bsfs)
+ ret = pkt->size;
+ else
+ ret = FFMIN(avci->compat_decode_consumed, pkt->size);
+ }
avci->compat_decode_consumed = 0;
avci->compat_decode_partial_size = (ret >= 0) ? pkt->size - ret : 0;
@@ -958,6 +1084,19 @@ void avcodec_flush_buffers(AVCodecContext *avctx)
else if (avctx->codec->flush)
avctx->codec->flush(avctx);
+ ff_decode_bsfs_uninit(avctx);
+
if (!avctx->refcounted_frames)
av_frame_unref(avctx->internal->to_free);
}
+
+void ff_decode_bsfs_uninit(AVCodecContext *avctx)
+{
+ DecodeFilterContext *s = &avctx->internal->filter;
+ int i;
+
+ for (i = 0; i < s->nb_bsfs; i++)
+ av_bsf_free(&s->bsfs[i]);
+ av_freep(&s->bsfs);
+ s->nb_bsfs = 0;
+}
diff --git a/libavcodec/decode.h b/libavcodec/decode.h
index 21c7c3e07a..c1e6457f77 100644
--- a/libavcodec/decode.h
+++ b/libavcodec/decode.h
@@ -32,4 +32,6 @@
*/
int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt);
+void ff_decode_bsfs_uninit(AVCodecContext *avctx);
+
#endif /* AVCODEC_DECODE_H */
diff --git a/libavcodec/internal.h b/libavcodec/internal.h
index dc24e8f764..796d45ff6e 100644
--- a/libavcodec/internal.h
+++ b/libavcodec/internal.h
@@ -99,6 +99,11 @@ typedef struct DecodeSimpleContext {
AVFrame *out_frame;
} DecodeSimpleContext;
+typedef struct DecodeFilterContext {
+ AVBSFContext **bsfs;
+ int nb_bsfs;
+} DecodeFilterContext;
+
typedef struct AVCodecInternal {
/**
* Whether the parent AVCodecContext is a copy of the context which had
@@ -136,6 +141,7 @@ typedef struct AVCodecInternal {
void *thread_ctx;
DecodeSimpleContext ds;
+ DecodeFilterContext filter;
/**
* Properties (timestamps+side data) extracted from the last packet passed
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 8a422d7669..2978109a23 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -40,6 +40,7 @@
#include "libavutil/samplefmt.h"
#include "libavutil/dict.h"
#include "avcodec.h"
+#include "decode.h"
#include "libavutil/opt.h"
#include "me_cmp.h"
#include "mpegvideo.h"
@@ -789,6 +790,8 @@ av_cold int avcodec_close(AVCodecContext *avctx)
avctx->hwaccel->uninit(avctx);
av_freep(&avctx->internal->hwaccel_priv_data);
+ ff_decode_bsfs_uninit(avctx);
+
av_freep(&avctx->internal);
}
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