Gif transparency fix

fftools/ffmpeg.c

@@ -847,7 +847,6 @@ static void output_packet(OutputFile *of, AVPacket *pkt,
                           OutputStream *ost, int eof)
 {
     int ret = 0;
-
     /* apply the output bitstream filters, if any */
     if (ost->nb_bitstream_filters) {
         int idx;
@@ -1291,6 +1290,8 @@ static void do_video_out(OutputFile *of,
 
         while (1) {
             ret = avcodec_receive_packet(enc, &pkt);
+            if (pkt.duration <= 0)
+                pkt.duration = av_rescale_q(in_picture->pkt_duration, ost->mux_timebase, enc->time_base);
             update_benchmark("encode_video %d.%d", ost->file_index, ost->index);
             if (ret == AVERROR(EAGAIN))
                 break;

libavcodec/avcodec.h

@@ -1376,6 +1376,12 @@ enum AVPacketSideDataType {
      */
     AV_PKT_DATA_A53_CC,
 
+    /**
+     * The disposal method that should be used with the frame. If missing,
+     * the frame will not be disposed. This contains exactly one byte.
+     */
+    AV_PKT_DATA_GIF_FRAME_DISPOSAL,
+
     /**
      * This side data is encryption initialization data.
      * The format is not part of ABI, use av_encryption_init_info_* methods to

libavcodec/gif.c

@@ -136,7 +136,7 @@ static void gif_crop_translucent(AVCodecContext *avctx,
         while (*y_start < y_end) {
             int is_trans = 1;
             for (int i = 0; i < w; i++) {
-                if (buf[w * *y_start + i] != trans) {
+                if (buf[linesize * *y_start + i] != trans) {
                     is_trans = 0;
                     break;
                 }
@@ -148,10 +148,10 @@ static void gif_crop_translucent(AVCodecContext *avctx,
         }
 
         // crop bottom
-        while (y_end < h) {
+        while (y_end > *y_start) {
             int is_trans = 1;
             for (int i = 0; i < w; i++) {
-                if (buf[w * y_end + i] != trans) {
+                if (buf[linesize * y_end + i] != trans) {
                     is_trans = 0;
                     break;
                 }
@@ -165,7 +165,7 @@ static void gif_crop_translucent(AVCodecContext *avctx,
         while (*x_start < x_end) {
             int is_trans = 1;
             for (int i = *y_start; i < y_end; i++) {
-                if (buf[w * i + *x_start] != trans) {
+                if (buf[linesize * i + *x_start] != trans) {
                     is_trans = 0;
                     break;
                 }
@@ -176,10 +176,10 @@ static void gif_crop_translucent(AVCodecContext *avctx,
         }
 
         // crop right
-        while (x_end < w) {
+        while (x_end > *x_start) {
             int is_trans = 1;
             for (int i = *y_start; i < y_end; i++) {
-                if (buf[w * i + x_end] != trans) {
+                if (buf[linesize * i + x_end] != trans) {
                     is_trans = 0;
                     break;
                 }
@@ -191,6 +191,7 @@ static void gif_crop_translucent(AVCodecContext *avctx,
 
         *height = y_end + 1 - *y_start;
         *width  = x_end + 1 - *x_start;
+
         av_log(avctx, AV_LOG_DEBUG,"%dx%d image at pos (%d;%d) [area:%dx%d]\n",
                *width, *height, *x_start, *y_start, avctx->width, avctx->height);
     }
@@ -267,7 +268,7 @@ static int gif_image_write_image(AVCodecContext *avctx,
     int bcid = -1, honor_transparency = (s->flags & GF_TRANSDIFF) && s->last_frame && !palette;
     const uint8_t *ptr;
 
-    if (!s->image && avctx->frame_number && is_image_translucent(avctx, buf, linesize)) {
+    if (!s->image && is_image_translucent(avctx, buf, linesize)) {
         gif_crop_translucent(avctx, buf, linesize, &width, &height, &x_start, &y_start);
         honor_transparency = 0;
         disposal = GCE_DISPOSAL_BACKGROUND;
@@ -497,4 +498,4 @@ AVCodec ff_gif_encoder = {
         AV_PIX_FMT_GRAY8, AV_PIX_FMT_PAL8, AV_PIX_FMT_NONE
     },
     .priv_class     = &gif_class,
-};
+};

libavdevice/indev_list.c

@@ -0,0 +1,4 @@
+static const AVInputFormat * const indev_list[] = {
+    &ff_avfoundation_demuxer,
+    &ff_lavfi_demuxer,
+    NULL };

libavdevice/outdev_list.c

@@ -0,0 +1,2 @@
+static const AVOutputFormat * const outdev_list[] = {
+    NULL };

libavformat/gif.c

@@ -88,6 +88,8 @@ static int gif_get_delay(GIFContext *gif, AVPacket *prev, AVPacket *new)
         gif->duration = av_clip_uint16(new->pts - prev->pts);
     else if (!new && gif->last_delay >= 0)
         gif->duration = gif->last_delay;
+    else
+        gif->duration = prev->duration;
 
     return gif->duration;
 }