[FFmpeg-devel] [PATCH 3/3] Adding support for encoding VP8 Alpha
Vignesh Venkatasubramanian
vigneshv at google.com
Thu May 9 01:59:33 CEST 2013
This patch adds support for encoding VP8 files with alpha. The alpha channel
is encoded separately and the output is placed in AVPacket's side_data. The
muxer then muxes it into the BlockAdditional element of the matroska container.
More details on spec here: http://goo.gl/wCP1y
Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
---
libavcodec/libvpxenc.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++--
libavformat/mux.c | 1 +
2 files changed, 96 insertions(+), 4 deletions(-)
diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
index 4f1adb8..f99e94c 100644
--- a/libavcodec/libvpxenc.c
+++ b/libavcodec/libvpxenc.c
@@ -33,6 +33,7 @@
#include "libavutil/avassert.h"
#include "libavutil/base64.h"
#include "libavutil/common.h"
+#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
@@ -43,6 +44,8 @@
struct FrameListData {
void *buf; /**< compressed data buffer */
size_t sz; /**< length of compressed data */
+ void *buf_alpha;
+ size_t sz_alpha;
int64_t pts; /**< time stamp to show frame
(in timebase units) */
unsigned long duration; /**< duration to show frame
@@ -58,6 +61,9 @@ typedef struct VP8EncoderContext {
AVClass *class;
struct vpx_codec_ctx encoder;
struct vpx_image rawimg;
+ struct vpx_codec_ctx encoder_alpha;
+ struct vpx_image rawimg_alpha;
+ uint8_t is_alpha;
struct vpx_fixed_buf twopass_stats;
int deadline; //i.e., RT/GOOD/BEST
uint64_t sse[4];
@@ -186,6 +192,8 @@ static void coded_frame_add(void *list, struct FrameListData *cx_frame)
static av_cold void free_coded_frame(struct FrameListData *cx_frame)
{
av_freep(&cx_frame->buf);
+ if (cx_frame->buf_alpha)
+ av_freep(&cx_frame->buf_alpha);
av_freep(&cx_frame);
}
@@ -226,6 +234,8 @@ static av_cold int vp8_free(AVCodecContext *avctx)
VP8Context *ctx = avctx->priv_data;
vpx_codec_destroy(&ctx->encoder);
+ if (ctx->is_alpha)
+ vpx_codec_destroy(&ctx->encoder_alpha);
av_freep(&ctx->twopass_stats.buf);
av_freep(&avctx->coded_frame);
av_freep(&avctx->stats_out);
@@ -238,12 +248,16 @@ static av_cold int vpx_init(AVCodecContext *avctx,
{
VP8Context *ctx = avctx->priv_data;
struct vpx_codec_enc_cfg enccfg;
+ struct vpx_codec_enc_cfg enccfg_alpha;
vpx_codec_flags_t flags = (avctx->flags & CODEC_FLAG_PSNR) ? VPX_CODEC_USE_PSNR : 0;
int res;
av_log(avctx, AV_LOG_INFO, "%s\n", vpx_codec_version_str());
av_log(avctx, AV_LOG_VERBOSE, "%s\n", vpx_codec_build_config());
+ if (avctx->pix_fmt == AV_PIX_FMT_YUVA420P)
+ ctx->is_alpha = 1;
+
if ((res = vpx_codec_enc_config_default(iface, &enccfg, 0)) != VPX_CODEC_OK) {
av_log(avctx, AV_LOG_ERROR, "Failed to get config: %s\n",
vpx_codec_err_to_string(res));
@@ -377,6 +391,15 @@ static av_cold int vpx_init(AVCodecContext *avctx,
return AVERROR(EINVAL);
}
+ if (ctx->is_alpha) {
+ enccfg_alpha = enccfg;
+ res = vpx_codec_enc_init(&ctx->encoder_alpha, iface, &enccfg_alpha, flags);
+ if (res != VPX_CODEC_OK) {
+ log_encoder_error(avctx, "Failed to initialize alpha encoder");
+ return AVERROR(EINVAL);
+ }
+ }
+
//codec control failures are currently treated only as warnings
av_log(avctx, AV_LOG_DEBUG, "vpx_codec_control\n");
if (ctx->cpu_used != INT_MIN)
@@ -404,6 +427,10 @@ static av_cold int vpx_init(AVCodecContext *avctx,
vpx_img_wrap(&ctx->rawimg, VPX_IMG_FMT_I420, avctx->width, avctx->height, 1,
(unsigned char*)1);
+ if (ctx->is_alpha)
+ vpx_img_wrap(&ctx->rawimg_alpha, VPX_IMG_FMT_I420, avctx->width, avctx->height, 1,
+ (unsigned char*)1);
+
avctx->coded_frame = avcodec_alloc_frame();
if (!avctx->coded_frame) {
av_log(avctx, AV_LOG_ERROR, "Error allocating coded frame\n");
@@ -415,6 +442,7 @@ static av_cold int vpx_init(AVCodecContext *avctx,
static inline void cx_pktcpy(struct FrameListData *dst,
const struct vpx_codec_cx_pkt *src,
+ const struct vpx_codec_cx_pkt *src_alpha,
VP8Context *ctx)
{
dst->pts = src->data.frame.pts;
@@ -438,6 +466,14 @@ static inline void cx_pktcpy(struct FrameListData *dst,
} else {
dst->frame_number = -1; /* sanity marker */
}
+ if (src_alpha) {
+ dst->buf_alpha = src_alpha->data.frame.buf;
+ dst->sz_alpha = src_alpha->data.frame.sz;
+ }
+ else {
+ dst->buf_alpha = NULL;
+ dst->sz_alpha = 0;
+ }
}
/**
@@ -451,6 +487,7 @@ static int storeframe(AVCodecContext *avctx, struct FrameListData *cx_frame,
AVPacket *pkt, AVFrame *coded_frame)
{
int ret = ff_alloc_packet2(avctx, pkt, cx_frame->sz);
+ uint8_t *side_data;
if (ret >= 0) {
memcpy(pkt->data, cx_frame->buf, pkt->size);
pkt->pts = pkt->dts = cx_frame->pts;
@@ -475,6 +512,18 @@ static int storeframe(AVCodecContext *avctx, struct FrameListData *cx_frame,
}
cx_frame->have_sse = 0;
}
+ if (cx_frame->sz_alpha > 0) {
+ side_data = av_packet_new_side_data(pkt,
+ AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL,
+ cx_frame->sz_alpha + 8);
+ if(side_data == NULL) {
+ av_free_packet(pkt);
+ av_free(pkt);
+ return AVERROR(ENOMEM);
+ }
+ AV_WB64(side_data, 1);
+ memcpy(side_data + 8, cx_frame->buf_alpha, cx_frame->sz_alpha);
+ }
} else {
return ret;
}
@@ -494,7 +543,9 @@ static int queue_frames(AVCodecContext *avctx, AVPacket *pkt_out,
{
VP8Context *ctx = avctx->priv_data;
const struct vpx_codec_cx_pkt *pkt;
+ const struct vpx_codec_cx_pkt *pkt_alpha = NULL;
const void *iter = NULL;
+ const void *iter_alpha = NULL;
int size = 0;
if (ctx->coded_frame_list) {
@@ -509,7 +560,9 @@ static int queue_frames(AVCodecContext *avctx, AVPacket *pkt_out,
/* consume all available output from the encoder before returning. buffers
are only good through the next vpx_codec call */
- while ((pkt = vpx_codec_get_cx_data(&ctx->encoder, &iter))) {
+ while ((pkt = vpx_codec_get_cx_data(&ctx->encoder, &iter)) &&
+ (!ctx->is_alpha ||
+ (ctx->is_alpha && (pkt_alpha = vpx_codec_get_cx_data(&ctx->encoder_alpha, &iter_alpha))))) {
switch (pkt->kind) {
case VPX_CODEC_CX_FRAME_PKT:
if (!size) {
@@ -518,7 +571,7 @@ static int queue_frames(AVCodecContext *avctx, AVPacket *pkt_out,
/* avoid storing the frame when the list is empty and we haven't yet
provided a frame for output */
av_assert0(!ctx->coded_frame_list);
- cx_pktcpy(&cx_frame, pkt, ctx);
+ cx_pktcpy(&cx_frame, pkt, pkt_alpha, ctx);
size = storeframe(avctx, &cx_frame, pkt_out, coded_frame);
if (size < 0)
return size;
@@ -531,7 +584,7 @@ static int queue_frames(AVCodecContext *avctx, AVPacket *pkt_out,
"Frame queue element alloc failed\n");
return AVERROR(ENOMEM);
}
- cx_pktcpy(cx_frame, pkt, ctx);
+ cx_pktcpy(cx_frame, pkt, pkt_alpha, ctx);
cx_frame->buf = av_malloc(cx_frame->sz);
if (!cx_frame->buf) {
@@ -542,6 +595,17 @@ static int queue_frames(AVCodecContext *avctx, AVPacket *pkt_out,
return AVERROR(ENOMEM);
}
memcpy(cx_frame->buf, pkt->data.frame.buf, pkt->data.frame.sz);
+ if (ctx->is_alpha) {
+ cx_frame->buf_alpha = av_malloc(cx_frame->sz_alpha);
+ if (!cx_frame->buf_alpha) {
+ av_log(avctx, AV_LOG_ERROR,
+ "Data buffer alloc (%zu bytes) failed\n",
+ cx_frame->sz_alpha);
+ av_free(cx_frame);
+ return AVERROR(ENOMEM);
+ }
+ memcpy(cx_frame->buf_alpha, pkt_alpha->data.frame.buf, pkt_alpha->data.frame.sz);
+ }
coded_frame_add(&ctx->coded_frame_list, cx_frame);
}
break;
@@ -580,6 +644,7 @@ static int vp8_encode(AVCodecContext *avctx, AVPacket *pkt,
{
VP8Context *ctx = avctx->priv_data;
struct vpx_image *rawimg = NULL;
+ struct vpx_image *rawimg_alpha = NULL;
int64_t timestamp = 0;
int res, coded_size;
vpx_enc_frame_flags_t flags = 0;
@@ -592,6 +657,17 @@ static int vp8_encode(AVCodecContext *avctx, AVPacket *pkt,
rawimg->stride[VPX_PLANE_Y] = frame->linesize[0];
rawimg->stride[VPX_PLANE_U] = frame->linesize[1];
rawimg->stride[VPX_PLANE_V] = frame->linesize[2];
+ if (ctx->is_alpha) {
+ uint8_t *u_plane, *v_plane;
+ rawimg_alpha = &ctx->rawimg_alpha;
+ rawimg_alpha->planes[VPX_PLANE_Y] = frame->data[3];
+ u_plane = av_malloc(frame->linesize[1] * frame->height);
+ memset(u_plane, 0x80, frame->linesize[1] * frame->height);
+ rawimg_alpha->planes[VPX_PLANE_U] = u_plane;
+ v_plane = av_malloc(frame->linesize[2] * frame->height);
+ memset(v_plane, 0x80, frame->linesize[2] * frame->height);
+ rawimg_alpha->planes[VPX_PLANE_V] = v_plane;
+ }
timestamp = frame->pts;
if (frame->pict_type == AV_PICTURE_TYPE_I)
flags |= VPX_EFLAG_FORCE_KF;
@@ -603,6 +679,16 @@ static int vp8_encode(AVCodecContext *avctx, AVPacket *pkt,
log_encoder_error(avctx, "Error encoding frame");
return AVERROR_INVALIDDATA;
}
+
+ if (ctx->is_alpha) {
+ res = vpx_codec_encode(&ctx->encoder_alpha, rawimg_alpha, timestamp,
+ avctx->ticks_per_frame, flags, ctx->deadline);
+ if (res != VPX_CODEC_OK) {
+ log_encoder_error(avctx, "Error encoding alpha frame");
+ return AVERROR_INVALIDDATA;
+ }
+ }
+
coded_size = queue_frames(avctx, pkt, avctx->coded_frame);
if (!frame && avctx->flags & CODEC_FLAG_PASS1) {
@@ -618,6 +704,11 @@ static int vp8_encode(AVCodecContext *avctx, AVPacket *pkt,
ctx->twopass_stats.sz);
}
+ if (rawimg_alpha) {
+ av_free(rawimg_alpha->planes[VPX_PLANE_U]);
+ av_free(rawimg_alpha->planes[VPX_PLANE_V]);
+ }
+
*got_packet = !!coded_size;
return 0;
}
@@ -692,7 +783,7 @@ AVCodec ff_libvpx_vp8_encoder = {
.encode2 = vp8_encode,
.close = vp8_free,
.capabilities = CODEC_CAP_DELAY | CODEC_CAP_AUTO_THREADS,
- .pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE },
+ .pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_NONE },
.long_name = NULL_IF_CONFIG_SMALL("libvpx VP8"),
.priv_class = &class_vp8,
.defaults = defaults,
diff --git a/libavformat/mux.c b/libavformat/mux.c
index 586137f..97fa5a4 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -586,6 +586,7 @@ int ff_interleave_add_packet(AVFormatContext *s, AVPacket *pkt,
#endif
pkt->buf = NULL;
av_dup_packet(&this_pktl->pkt); // duplicate the packet if it uses non-allocated memory
+ av_copy_packet_side_data(&this_pktl->pkt, &this_pktl->pkt); // copy side data
if (s->streams[pkt->stream_index]->last_in_packet_buffer) {
next_point = &(st->last_in_packet_buffer->next);
--
1.8.2.1
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