* Restructuring the division of labor between DV codec and DV format

    [ Based on a patch by Brian Brice (bbrice at newtek dot com) ]

Originally committed as revision 6161 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 125 insertions, 12 deletions

diff --git a/libavcodec/dv.c b/libavcodec/dv.c
index 90d101813b..fa2952dc65 100644
--- a/libavcodec/dv.c
+++ b/libavcodec/dv.c
@@ -1069,6 +1069,130 @@ static int dvvideo_decode_frame(AVCodecContext *avctx,
     return s->sys->frame_size;
 }
 
+
+static inline int dv_write_pack(enum dv_pack_type pack_id, DVVideoContext *c, uint8_t* buf)
+{
+    /*
+     * Here's what SMPTE314M says about these two:
+     *    (page 6) APTn, AP1n, AP2n, AP3n: These data shall be identical
+     *             as track application IDs (APTn = 001, AP1n =
+     *             001, AP2n = 001, AP3n = 001), if the source signal
+     *             comes from a digital VCR. If the signal source is
+     *             unknown, all bits for these data shall be set to 1.
+     *    (page 12) STYPE: STYPE defines a signal type of video signal
+     *                     00000b = 4:1:1 compression
+     *                     00100b = 4:2:2 compression
+     *                     XXXXXX = Reserved
+     * Now, I've got two problems with these statements:
+     *   1. it looks like APT == 111b should be a safe bet, but it isn't.
+     *      It seems that for PAL as defined in IEC 61834 we have to set
+     *      APT to 000 and for SMPTE314M to 001.
+     *   2. It is not at all clear what STYPE is used for 4:2:0 PAL
+     *      compression scheme (if any).
+     */
+    int apt = (c->sys->pix_fmt == PIX_FMT_YUV420P ? 0 : 1);
+    int stype = (c->sys->pix_fmt == PIX_FMT_YUV422P ? 4 : 0);
+
+    uint8_t aspect = 0;
+    if((int)(av_q2d(c->avctx->sample_aspect_ratio) * c->avctx->width / c->avctx->height * 10) == 17) /* 16:9 */
+        aspect = 0x02;
+
+    buf[0] = (uint8_t)pack_id;
+    switch (pack_id) {
+    case dv_header525: /* I can't imagine why these two weren't defined as real */
+    case dv_header625: /* packs in SMPTE314M -- they definitely look like ones */
+          buf[1] = 0xf8 |               /* reserved -- always 1 */
+                   (apt & 0x07);        /* APT: Track application ID */
+          buf[2] = (0 << 7)    | /* TF1: audio data is 0 - valid; 1 - invalid */
+                   (0x0f << 3) | /* reserved -- always 1 */
+                   (apt & 0x07); /* AP1: Audio application ID */
+          buf[3] = (0 << 7)    | /* TF2: video data is 0 - valid; 1 - invalid */
+                   (0x0f << 3) | /* reserved -- always 1 */
+                   (apt & 0x07); /* AP2: Video application ID */
+          buf[4] = (0 << 7)    | /* TF3: subcode(SSYB) is 0 - valid; 1 - invalid */
+                   (0x0f << 3) | /* reserved -- always 1 */
+                   (apt & 0x07); /* AP3: Subcode application ID */
+          break;
+    case dv_video_source:
+          buf[1] = 0xff; /* reserved -- always 1 */
+          buf[2] = (1 << 7) | /* B/W: 0 - b/w, 1 - color */
+                   (1 << 6) | /* following CLF is valid - 0, invalid - 1 */
+                   (3 << 4) | /* CLF: color frames id (see ITU-R BT.470-4) */
+                   0xf; /* reserved -- always 1 */
+          buf[3] = (3 << 6) | /* reserved -- always 1 */
+                   (c->sys->dsf << 5) | /*  system: 60fields/50fields */
+                   stype; /* signal type video compression */
+          buf[4] = 0xff; /* VISC: 0xff -- no information */
+          break;
+    case dv_video_control:
+          buf[1] = (0 << 6) | /* Copy generation management (CGMS) 0 -- free */
+                   0x3f; /* reserved -- always 1 */
+          buf[2] = 0xc8 | /* reserved -- always b11001xxx */
+                   aspect;
+          buf[3] = (1 << 7) | /* Frame/field flag 1 -- frame, 0 -- field */
+                   (1 << 6) | /* First/second field flag 0 -- field 2, 1 -- field 1 */
+                   (1 << 5) | /* Frame change flag 0 -- same picture as before, 1 -- different */
+                   (1 << 4) | /* 1 - interlaced, 0 - noninterlaced */
+                   0xc; /* reserved -- always b1100 */
+          buf[4] = 0xff; /* reserved -- always 1 */
+          break;
+    default:
+          buf[1] = buf[2] = buf[3] = buf[4] = 0xff;
+    }
+    return 5;
+}
+
+static void dv_format_frame(DVVideoContext* c, uint8_t* buf)
+{
+    int chan, i, j, k;
+
+    for (chan = 0; chan < c->sys->n_difchan; chan++) {
+        for (i = 0; i < c->sys->difseg_size; i++) {
+            memset(buf, 0xff, 80 * 6); /* First 6 DIF blocks are for control data */
+
+            /* DV header: 1DIF */
+            buf += dv_write_dif_id(dv_sect_header, chan, i, 0, buf);
+            buf += dv_write_pack((c->sys->dsf ? dv_header625 : dv_header525), c, buf);
+            buf += 72; /* unused bytes */
+
+            /* DV subcode: 2DIFs */
+            for (j = 0; j < 2; j++) {
+                buf += dv_write_dif_id(dv_sect_subcode, chan, i, j, buf);
+                for (k = 0; k < 6; k++)
+                     buf += dv_write_ssyb_id(k, (i < c->sys->difseg_size/2), buf) + 5;
+                buf += 29; /* unused bytes */
+            }
+
+            /* DV VAUX: 3DIFS */
+            for (j = 0; j < 3; j++) {
+                buf += dv_write_dif_id(dv_sect_vaux, chan, i, j, buf);
+                buf += dv_write_pack(dv_video_source,  c, buf);
+                buf += dv_write_pack(dv_video_control, c, buf);
+                buf += 7*5;
+                buf += dv_write_pack(dv_video_source,  c, buf);
+                buf += dv_write_pack(dv_video_control, c, buf);
+                buf += 4*5 + 2; /* unused bytes */
+            }
+
+            /* DV Audio/Video: 135 Video DIFs + 9 Audio DIFs */
+            for (j = 0; j < 135; j++) {
+                if (j%15 == 0) {
+                    memset(buf, 0xff, 80);
+                    buf += dv_write_dif_id(dv_sect_audio, chan, i, j/15, buf);
+                    buf += 77; /* audio control & shuffled PCM audio */
+                }
+                buf += dv_write_dif_id(dv_sect_video, chan, i, j, buf);
+                buf += 77; /* 1 video macro block: 1 bytes control
+                              4 * 14 bytes Y 8x8 data
+                              10 bytes Cr 8x8 data
+                              10 bytes Cb 8x8 data */
+            }
+        }
+    }
+}
+
+
+
 static int dvvideo_encode_frame(AVCodecContext *c, uint8_t *buf, int buf_size,
                                 void *data)
 {
@@ -1091,18 +1215,7 @@ static int dvvideo_encode_frame(AVCodecContext *c, uint8_t *buf, int buf_size,
 
     emms_c();
 
-    /* Fill in just enough of the header for dv_frame_profile() to
-       return the correct result, so that the frame can be decoded
-       correctly. The rest of the metadata is filled in by the dvvideo
-       avformat. (this should probably change so that encode_frame()
-       fills in ALL of the metadata - e.g. for Quicktime-wrapped DV
-       streams) */
-
-    /* NTSC/PAL format */
-    buf[3] = s->sys->dsf ? 0x80 : 0x00;
-
-    /* 25Mbps or 50Mbps */
-    buf[80*5 + 48 + 3] = (s->sys->pix_fmt == PIX_FMT_YUV422P) ? 0x4 : 0x0;
+    dv_format_frame(s, buf);
 
     return s->sys->frame_size;
 }