[FFmpeg-devel] [PATCH v2] libavcodec/mediacodecdec: switch to new decoder api

Matthieu Bouron matthieu.bouron at gmail.com
Wed Jan 3 13:25:30 EET 2018


On Thu, Dec 28, 2017 at 05:33:14PM -0800, Aman Gupta wrote:
> From: Aman Gupta <aman at tmm1.net>
> 
> Using the new API gives the decoder the ability to produce
> N frames per input packet. This is particularly useful with
> mpeg2 decoders on some android devices, which automatically
> deinterlace video and produce one frame per field.
> 
> Signed-off-by: Aman Gupta <aman at tmm1.net>
> ---
>  libavcodec/mediacodecdec.c | 77 +++++++++++++++++++++++++++-------------------
>  1 file changed, 45 insertions(+), 32 deletions(-)

Hi,

Thanks for the patch.

I'm attaching a new version of your patch. The new version fixes some
issues that appear while seeking or when the decoder reaches EOF.

The following comments correspond to the changes I made in the new patch
(except for a few minor cosmetics like = {0}; -> = { 0 };).

> 
> diff --git a/libavcodec/mediacodecdec.c b/libavcodec/mediacodecdec.c
> index b698ceaef9..90497c64da 100644
> --- a/libavcodec/mediacodecdec.c
> +++ b/libavcodec/mediacodecdec.c
> @@ -31,6 +31,7 @@
>  #include "libavutil/pixfmt.h"
>  
>  #include "avcodec.h"
> +#include "decode.h"
>  #include "h264_parse.h"
>  #include "hevc_parse.h"
>  #include "hwaccel.h"
> @@ -424,29 +425,13 @@ static int mediacodec_process_data(AVCodecContext *avctx, AVFrame *frame,
>      return ff_mediacodec_dec_decode(avctx, s->ctx, frame, got_frame, pkt);
>  }
>  
> -static int mediacodec_decode_frame(AVCodecContext *avctx, void *data,
> -                                   int *got_frame, AVPacket *avpkt)
> +static int mediacodec_receive_frame(AVCodecContext *avctx, AVFrame *frame)
>  {
>      MediaCodecH264DecContext *s = avctx->priv_data;
> -    AVFrame *frame    = data;
>      int ret;
> -
> -    /* buffer the input packet */
> -    if (avpkt->size) {
> -        AVPacket input_pkt = { 0 };
> -
> -        if (av_fifo_space(s->fifo) < sizeof(input_pkt)) {
> -            ret = av_fifo_realloc2(s->fifo,
> -                                   av_fifo_size(s->fifo) + sizeof(input_pkt));
> -            if (ret < 0)
> -                return ret;
> -        }
> -
> -        ret = av_packet_ref(&input_pkt, avpkt);
> -        if (ret < 0)
> -            return ret;
> -        av_fifo_generic_write(s->fifo, &input_pkt, sizeof(input_pkt), NULL);
> -    }
> +    int got_frame = 0;
> +    int is_eof = 0;
> +    AVPacket pkt = {0};
>  
>      /*
>       * MediaCodec.flush() discards both input and output buffers, thus we
> @@ -470,26 +455,51 @@ static int mediacodec_decode_frame(AVCodecContext *avctx, void *data,
>       */
>      if (ff_mediacodec_dec_is_flushing(avctx, s->ctx)) {
>          if (!ff_mediacodec_dec_flush(avctx, s->ctx)) {
> -            return avpkt->size;
> +            return 0;
>          }
> +        return AVERROR(EAGAIN);

You should only return AVERROR(EAGAIN) if ff_mediacodec_dec_flush returns
0:
    if (ff_mediacodec_dec_is_flushing(avctx, s->ctx)) {
        if (!ff_mediacodec_dec_flush(avctx, s->ctx)) {
            return AVERROR(EAGAIN);
        }
    }

> +    }
> +
> +    ret = ff_decode_get_packet(avctx, &pkt);
> +    if (ret == AVERROR_EOF)
> +        is_eof = 1;
> +    else if (ret == AVERROR(EAGAIN))
> +        ; // no input packet, but fallthrough to check for pending frames
> +    else if (ret < 0)
> +        return ret;
> +
> +    /* buffer the input packet */
> +    if (pkt.size) {
> +        if (av_fifo_space(s->fifo) < sizeof(pkt)) {
> +            ret = av_fifo_realloc2(s->fifo,
> +                                   av_fifo_size(s->fifo) + sizeof(pkt));
> +            if (ret < 0) {
> +                av_packet_unref(&pkt);
> +                return ret;
> +            }
> +        }
> +        av_fifo_generic_write(s->fifo, &pkt, sizeof(pkt), NULL);
>      }
>  
>      /* process buffered data */
> -    while (!*got_frame) {
> +    while (!got_frame) {
>          /* prepare the input data */
>          if (s->buffered_pkt.size <= 0) {
>              av_packet_unref(&s->buffered_pkt);
>  
>              /* no more data */
>              if (av_fifo_size(s->fifo) < sizeof(AVPacket)) {
> -                return avpkt->size ? avpkt->size :
> -                    ff_mediacodec_dec_decode(avctx, s->ctx, frame, got_frame, avpkt);
> +                AVPacket null_pkt = {0};
> +                if (is_eof)
> +                    return ff_mediacodec_dec_decode(avctx, s->ctx, frame,
> +                                                    &got_frame, &null_pkt);

Returning the return value of ff_mediacodec_dec_decode is not valid. It
should be something like:
    ret = ff_mediacodec_dec_decode(avctx, s->ctx, frame,
                                   &got_frame, &null_pkt);
    if (ret < 0)
        return ret;
    else if (got_frame)
        return 0;
    else
        return AVERROR_EOF;

> +                return AVERROR(EAGAIN);
>              }
>  
>              av_fifo_generic_read(s->fifo, &s->buffered_pkt, sizeof(s->buffered_pkt), NULL);
>          }
>  
> -        ret = mediacodec_process_data(avctx, frame, got_frame, &s->buffered_pkt);
> +        ret = mediacodec_process_data(avctx, frame, &got_frame, &s->buffered_pkt);
>          if (ret < 0)
>              return ret;
>  
> @@ -497,7 +507,10 @@ static int mediacodec_decode_frame(AVCodecContext *avctx, void *data,
>          s->buffered_pkt.data += ret;
>      }
>  
> -    return avpkt->size;
> +    if (got_frame)
> +        return 0;
> +
> +    return AVERROR(EAGAIN);

got_frame is always 1 here, returning 0 should be enough.

[...]

Let me know if the attached updated patch works for you.

Best regards,

-- 
Matthieu B.
-------------- next part --------------
>From 1f2bd9721973de9a4d83f5b2c9a5f1de793f641d Mon Sep 17 00:00:00 2001
From: Aman Gupta <aman at tmm1.net>
Date: Thu, 28 Dec 2017 17:33:14 -0800
Subject: [PATCH] libavcodec/mediacodecdec: switch to new decoder api

Using the new API gives the decoder the ability to produce
N frames per input packet. This is particularly useful with
mpeg2 decoders on some android devices, which automatically
deinterlace video and produce one frame per field.

Signed-off-by: Aman Gupta <aman at tmm1.net>
Signed-off-by: Matthieu Bouron <matthieu.bouron at gmail.com>
---
 libavcodec/mediacodecdec.c | 80 +++++++++++++++++++++++++++-------------------
 1 file changed, 48 insertions(+), 32 deletions(-)

diff --git a/libavcodec/mediacodecdec.c b/libavcodec/mediacodecdec.c
index 3460478f43..94bff039a6 100644
--- a/libavcodec/mediacodecdec.c
+++ b/libavcodec/mediacodecdec.c
@@ -31,6 +31,7 @@
 #include "libavutil/pixfmt.h"
 
 #include "avcodec.h"
+#include "decode.h"
 #include "h264_parse.h"
 #include "hevc_parse.h"
 #include "hwaccel.h"
@@ -442,29 +443,13 @@ static int mediacodec_process_data(AVCodecContext *avctx, AVFrame *frame,
     return ff_mediacodec_dec_decode(avctx, s->ctx, frame, got_frame, pkt);
 }
 
-static int mediacodec_decode_frame(AVCodecContext *avctx, void *data,
-                                   int *got_frame, AVPacket *avpkt)
+static int mediacodec_receive_frame(AVCodecContext *avctx, AVFrame *frame)
 {
     MediaCodecH264DecContext *s = avctx->priv_data;
-    AVFrame *frame    = data;
     int ret;
-
-    /* buffer the input packet */
-    if (avpkt->size) {
-        AVPacket input_pkt = { 0 };
-
-        if (av_fifo_space(s->fifo) < sizeof(input_pkt)) {
-            ret = av_fifo_realloc2(s->fifo,
-                                   av_fifo_size(s->fifo) + sizeof(input_pkt));
-            if (ret < 0)
-                return ret;
-        }
-
-        ret = av_packet_ref(&input_pkt, avpkt);
-        if (ret < 0)
-            return ret;
-        av_fifo_generic_write(s->fifo, &input_pkt, sizeof(input_pkt), NULL);
-    }
+    int got_frame = 0;
+    int is_eof = 0;
+    AVPacket pkt = { 0 };
 
     /*
      * MediaCodec.flush() discards both input and output buffers, thus we
@@ -488,26 +473,57 @@ static int mediacodec_decode_frame(AVCodecContext *avctx, void *data,
      */
     if (ff_mediacodec_dec_is_flushing(avctx, s->ctx)) {
         if (!ff_mediacodec_dec_flush(avctx, s->ctx)) {
-            return avpkt->size;
+            return AVERROR(EAGAIN);
         }
     }
 
+    ret = ff_decode_get_packet(avctx, &pkt);
+    if (ret == AVERROR_EOF)
+        is_eof = 1;
+    else if (ret == AVERROR(EAGAIN))
+        ; /* no input packet, but fallthrough to check for pending frames */
+    else if (ret < 0)
+        return ret;
+
+    /* buffer the input packet */
+    if (pkt.size) {
+        if (av_fifo_space(s->fifo) < sizeof(pkt)) {
+            ret = av_fifo_realloc2(s->fifo,
+                                   av_fifo_size(s->fifo) + sizeof(pkt));
+            if (ret < 0) {
+                av_packet_unref(&pkt);
+                return ret;
+            }
+        }
+        av_fifo_generic_write(s->fifo, &pkt, sizeof(pkt), NULL);
+    }
+
     /* process buffered data */
-    while (!*got_frame) {
+    while (!got_frame) {
         /* prepare the input data */
         if (s->buffered_pkt.size <= 0) {
             av_packet_unref(&s->buffered_pkt);
 
             /* no more data */
             if (av_fifo_size(s->fifo) < sizeof(AVPacket)) {
-                return avpkt->size ? avpkt->size :
-                    ff_mediacodec_dec_decode(avctx, s->ctx, frame, got_frame, avpkt);
+                AVPacket null_pkt = { 0 };
+                if (is_eof) {
+                    ret = ff_mediacodec_dec_decode(avctx, s->ctx, frame,
+                                                   &got_frame, &null_pkt);
+                    if (ret < 0)
+                        return ret;
+                    else if (got_frame)
+                        return 0;
+                    else
+                        return AVERROR_EOF;
+                }
+                return AVERROR(EAGAIN);
             }
 
             av_fifo_generic_read(s->fifo, &s->buffered_pkt, sizeof(s->buffered_pkt), NULL);
         }
 
-        ret = mediacodec_process_data(avctx, frame, got_frame, &s->buffered_pkt);
+        ret = mediacodec_process_data(avctx, frame, &got_frame, &s->buffered_pkt);
         if (ret < 0)
             return ret;
 
@@ -515,7 +531,7 @@ static int mediacodec_decode_frame(AVCodecContext *avctx, void *data,
         s->buffered_pkt.data += ret;
     }
 
-    return avpkt->size;
+    return 0;
 }
 
 static void mediacodec_decode_flush(AVCodecContext *avctx)
@@ -555,7 +571,7 @@ AVCodec ff_h264_mediacodec_decoder = {
     .id             = AV_CODEC_ID_H264,
     .priv_data_size = sizeof(MediaCodecH264DecContext),
     .init           = mediacodec_decode_init,
-    .decode         = mediacodec_decode_frame,
+    .receive_frame  = mediacodec_receive_frame,
     .flush          = mediacodec_decode_flush,
     .close          = mediacodec_decode_close,
     .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AVOID_PROBING | AV_CODEC_CAP_HARDWARE,
@@ -574,7 +590,7 @@ AVCodec ff_hevc_mediacodec_decoder = {
     .id             = AV_CODEC_ID_HEVC,
     .priv_data_size = sizeof(MediaCodecH264DecContext),
     .init           = mediacodec_decode_init,
-    .decode         = mediacodec_decode_frame,
+    .receive_frame  = mediacodec_receive_frame,
     .flush          = mediacodec_decode_flush,
     .close          = mediacodec_decode_close,
     .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AVOID_PROBING | AV_CODEC_CAP_HARDWARE,
@@ -593,7 +609,7 @@ AVCodec ff_mpeg2_mediacodec_decoder = {
     .id             = AV_CODEC_ID_MPEG2VIDEO,
     .priv_data_size = sizeof(MediaCodecH264DecContext),
     .init           = mediacodec_decode_init,
-    .decode         = mediacodec_decode_frame,
+    .receive_frame  = mediacodec_receive_frame,
     .flush          = mediacodec_decode_flush,
     .close          = mediacodec_decode_close,
     .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AVOID_PROBING | AV_CODEC_CAP_HARDWARE,
@@ -611,7 +627,7 @@ AVCodec ff_mpeg4_mediacodec_decoder = {
     .id             = AV_CODEC_ID_MPEG4,
     .priv_data_size = sizeof(MediaCodecH264DecContext),
     .init           = mediacodec_decode_init,
-    .decode         = mediacodec_decode_frame,
+    .receive_frame  = mediacodec_receive_frame,
     .flush          = mediacodec_decode_flush,
     .close          = mediacodec_decode_close,
     .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AVOID_PROBING | AV_CODEC_CAP_HARDWARE,
@@ -629,7 +645,7 @@ AVCodec ff_vp8_mediacodec_decoder = {
     .id             = AV_CODEC_ID_VP8,
     .priv_data_size = sizeof(MediaCodecH264DecContext),
     .init           = mediacodec_decode_init,
-    .decode         = mediacodec_decode_frame,
+    .receive_frame  = mediacodec_receive_frame,
     .flush          = mediacodec_decode_flush,
     .close          = mediacodec_decode_close,
     .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AVOID_PROBING | AV_CODEC_CAP_HARDWARE,
@@ -647,7 +663,7 @@ AVCodec ff_vp9_mediacodec_decoder = {
     .id             = AV_CODEC_ID_VP9,
     .priv_data_size = sizeof(MediaCodecH264DecContext),
     .init           = mediacodec_decode_init,
-    .decode         = mediacodec_decode_frame,
+    .receive_frame  = mediacodec_receive_frame,
     .flush          = mediacodec_decode_flush,
     .close          = mediacodec_decode_close,
     .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AVOID_PROBING | AV_CODEC_CAP_HARDWARE,
-- 
2.15.1



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